Carve booleans library integration

==================================

Merging Carve library integration project into the trunk.

This commit switches Boolean modifier to another library which handles
mesh boolean operations in much stable and faster way, resolving old
well-known limitations of intern boolop library.

Carve is integrating as alternative interface for boolop library and
which makes it totally transparent for blender sources to switch between
old-fashioned boolop and new Carve backends.

Detailed changes in this commit:

- Integrated needed subset of Carve library sources into extern/
  Added script for re-bundling it (currently works only if repo
  was cloned by git-svn).
- Added BOP_CarveInterface for boolop library which can be used by
  Boolean modifier.
- Carve backend is enabled by default, can be disabled by WITH_BF_CARVE
  SCons option and WITH_CARVE CMake option.
- If Boost library is found in build environment it'll be used for
  unordered collections. If Boost isn't found, it'll fallback to TR1
  implementation for GCC compilers. Boost is obligatory if MSVC is used.

Tested on Linux 64bit and Windows 7 64bit.

NOTE: behavior of flat objects was changed. E.g. Plane-Sphere now gives
      plane with circle hole, not plane with semisphere. Don't think
      it's really issue because it's not actually defined behavior in
      such situations and both of ways might be useful. Since it's
      only known "regression" think it's OK to deal with it.

Details are there http://wiki.blender.org/index.php/User:Nazg-gul/CarveBooleans

Special thanks to:

- Ken Hughes: author of original carve integration patch.
- Campbell Barton: help in project development, review tests.
- Tobias Sargeant: author of Carve library, help in resolving some
                   merge stoppers, bug fixing.

75 files changed, 16562 insertions, 0 deletions

diff --git a/extern/carve/include/carve/aabb.hpp b/extern/carve/include/carve/aabb.hpp
new file mode 100644
index 00000000000..20ee028aa45
--- /dev/null
+++ b/extern/carve/include/carve/aabb.hpp
@@ -0,0 +1,150 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom.hpp>
+
+#include <vector>
+
+namespace carve {
+  namespace geom {
+
+
+
+    // n-dimensional AABB
+    template<unsigned ndim>
+    struct aabb {
+      typedef vector<ndim> vector_t;
+      typedef aabb<ndim> aabb_t;
+
+      vector_t pos;     // the centre of the AABB
+      vector_t extent;  // the extent of the AABB - the vector from the centre to the maximal vertex.
+
+      void empty();
+
+      bool isEmpty() const;
+
+      void fit(const vector_t &v1);
+      void fit(const vector_t &v1, const vector_t &v2);
+      void fit(const vector_t &v1, const vector_t &v2, const vector_t &v3);
+
+      template<typename iter_t, typename value_type>
+      void _fit(iter_t begin, iter_t end, value_type);
+
+      template<typename iter_t>
+      void _fit(iter_t begin, iter_t end, vector_t);
+
+      template<typename iter_t>
+      void _fit(iter_t begin, iter_t end, aabb_t);
+
+      template<typename iter_t>
+      void fit(iter_t begin, iter_t end);
+
+      template<typename iter_t, typename adapt_t>
+      void fit(iter_t begin, iter_t end, adapt_t adapt);
+
+      void unionAABB(const aabb<ndim> &a);
+
+      void expand(double pad);
+
+      bool completelyContains(const aabb<ndim> &other) const;
+
+      bool containsPoint(const vector_t &v) const;
+
+      bool intersectsLineSegment(const vector_t &v1, const vector_t &v2) const;
+
+      double axisSeparation(const aabb<ndim> &other, unsigned axis) const;
+
+      double maxAxisSeparation(const aabb<ndim> &other) const;
+
+      bool intersects(const aabb<ndim> &other) const;
+      bool intersects(const sphere<ndim> &s) const;
+      bool intersects(const plane<ndim> &plane) const;
+      bool intersects(const ray<ndim> &ray) const;
+      bool intersects(tri<ndim> tri) const;
+      bool intersects(const linesegment<ndim> &ls) const;
+
+      std::pair<double, double> rangeInDirection(const carve::geom::vector<ndim> &v) const;
+
+      vector_t min() const;
+      vector_t mid() const;
+      vector_t max() const;
+
+      double min(unsigned dim) const;
+      double mid(unsigned dim) const;
+      double max(unsigned dim) const;
+
+      double volume() const;
+
+      int compareAxis(const axis_pos &ap) const;
+
+      void constrainMax(const axis_pos &ap);
+      void constrainMin(const axis_pos &ap);
+
+      aabb getAABB() const;
+
+      aabb(const vector_t &_pos = vector_t::ZERO(),
+           const vector_t &_extent = vector_t::ZERO());
+
+      template<typename iter_t, typename adapt_t>
+      aabb(iter_t begin, iter_t end, adapt_t adapt);
+
+      template<typename iter_t>
+      aabb(iter_t begin, iter_t end);
+
+      aabb(const aabb<ndim> &a, const aabb<ndim> &b);
+    };
+
+    template<unsigned ndim>
+    bool operator==(const aabb<ndim> &a, const aabb<ndim> &b);
+
+    template<unsigned ndim>
+    bool operator!=(const aabb<ndim> &a, const aabb<ndim> &b);
+
+    template<unsigned ndim>
+    std::ostream &operator<<(std::ostream &o, const aabb<ndim> &a);
+
+
+
+    template<unsigned ndim, typename obj_t>
+    struct get_aabb {
+      aabb<ndim> operator()(const obj_t &obj) const {
+        return obj.getAABB();
+      }
+    };
+
+    template<unsigned ndim, typename obj_t>
+    struct get_aabb<ndim, obj_t *> {
+      aabb<ndim> operator()(const obj_t *obj) const {
+        return obj->getAABB();
+      }
+    };
+
+
+
+  }
+}
+
+namespace carve {
+  namespace geom3d {
+    typedef carve::geom::aabb<3> AABB;
+  }
+}
+
+#include <carve/aabb_impl.hpp>
diff --git a/extern/carve/include/carve/aabb_impl.hpp b/extern/carve/include/carve/aabb_impl.hpp
new file mode 100644
index 00000000000..ccdddef160b
--- /dev/null
+++ b/extern/carve/include/carve/aabb_impl.hpp
@@ -0,0 +1,423 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/vector.hpp>
+#include <carve/geom3d.hpp>
+
+#include <carve/geom.hpp>
+
+#include <vector>
+
+namespace carve {
+  namespace geom {
+
+    template<unsigned ndim>
+    void aabb<ndim>::empty() {
+      pos.setZero();
+      extent.setZero();
+    }
+
+    template<unsigned ndim>
+    bool aabb<ndim>::isEmpty() const {
+      return extent.exactlyZero();
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t, typename value_type>
+    void aabb<ndim>::_fit(iter_t begin, iter_t end, value_type) {
+      if (begin == end) {
+        empty();
+        return;
+      }
+
+      vector_t min, max;
+      aabb<ndim> a = get_aabb<ndim, value_type>()(*begin); ++begin;
+      min = a.min();
+      max = a.max();
+      while (begin != end) {
+        aabb<ndim> a = get_aabb<ndim, value_type>()(*begin); ++begin;
+        assign_op(min, min, a.min(), carve::util::min_functor());
+        assign_op(max, max, a.max(), carve::util::max_functor());
+      }
+
+      pos = (min + max) / 2.0;
+      assign_op(extent, max - pos, pos - min, carve::util::max_functor());
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void aabb<ndim>::_fit(iter_t begin, iter_t end, vector_t) {
+      if (begin == end) {
+        empty();
+        return;
+      }
+
+      vector_t min, max;
+      bounds(begin, end, min, max);
+      pos = (min + max) / 2.0;
+      assign_op(extent, max - pos, pos - min, carve::util::max_functor());
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void aabb<ndim>::_fit(iter_t begin, iter_t end, aabb_t) {
+      if (begin == end) {
+        empty();
+        return;
+      }
+
+      vector_t min, max;
+      aabb<ndim> a = *begin++;
+      min = a.min();
+      max = a.max();
+      while (begin != end) {
+        aabb<ndim> a = *begin; ++begin;
+        assign_op(min, min, a.min(), carve::util::min_functor());
+        assign_op(max, max, a.max(), carve::util::max_functor());
+      }
+
+      pos = (min + max) / 2.0;
+      assign_op(extent, max - pos, pos - min, carve::util::max_functor());
+    }
+
+    template<unsigned ndim>
+    void aabb<ndim>::fit(const vector_t &v1) {
+      pos = v1;
+      extent.setZero();
+    }
+
+    template<unsigned ndim>
+    void aabb<ndim>::fit(const vector_t &v1, const vector_t &v2) {
+      vector_t min, max;
+      assign_op(min, v1, v2, carve::util::min_functor());
+      assign_op(max, v1, v2, carve::util::max_functor());
+
+      pos = (min + max) / 2.0;
+      assign_op(extent, max - pos, pos - min, carve::util::max_functor());
+    }
+
+    template<unsigned ndim>
+    void aabb<ndim>::fit(const vector_t &v1, const vector_t &v2, const vector_t &v3) {
+      vector_t min, max;
+      min = max = v1;
+
+      assign_op(min, min, v2, carve::util::min_functor());
+      assign_op(max, max, v2, carve::util::max_functor());
+      assign_op(min, min, v3, carve::util::min_functor());
+      assign_op(max, max, v3, carve::util::max_functor());
+
+      pos = (min + max) / 2.0;
+      assign_op(extent, max - pos, pos - min, carve::util::max_functor());
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t, typename adapt_t>
+    void aabb<ndim>::fit(iter_t begin, iter_t end, adapt_t adapt) {
+      vector_t min, max;
+
+      bounds(begin, end, adapt, min, max);
+      pos = (min + max) / 2.0;
+      assign_op(extent, max - pos, pos - min, carve::util::max_functor());
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void aabb<ndim>::fit(iter_t begin, iter_t end) {
+      _fit(begin, end, typename std::iterator_traits<iter_t>::value_type());
+    }
+
+    template<unsigned ndim>
+    void aabb<ndim>::expand(double pad) {
+      extent += pad;
+    }
+
+    template<unsigned ndim>
+    void aabb<ndim>::unionAABB(const aabb<ndim> &a) {
+      vector_t vmin, vmax;
+
+      assign_op(vmin, min(), a.min(), carve::util::min_functor());
+      assign_op(vmax, max(), a.max(), carve::util::max_functor());
+      pos = (vmin + vmax) / 2.0;
+      assign_op(extent, vmax - pos, pos - vmin, carve::util::max_functor());
+    }
+
+    template<unsigned ndim>
+    bool aabb<ndim>::completelyContains(const aabb<ndim> &other) const {
+      for (unsigned i = 0; i < ndim; ++i) {
+        if (fabs(other.pos.v[i] - pos.v[i]) + other.extent.v[i] > extent.v[i]) return false;
+      }
+      return true;
+    }
+
+    template<unsigned ndim>
+    bool aabb<ndim>::containsPoint(const vector_t &v) const {
+      for (unsigned i = 0; i < ndim; ++i) {
+        if (fabs(v.v[i] - pos.v[i]) > extent.v[i]) return false;
+      }
+      return true;
+    }
+
+    template<unsigned ndim>
+    double aabb<ndim>::axisSeparation(const aabb<ndim> &other, unsigned axis) const {
+      return fabs(other.pos.v[axis] - pos.v[axis]) - extent.v[axis] - other.extent.v[axis];
+    }
+
+    template<unsigned ndim>
+    double aabb<ndim>::maxAxisSeparation(const aabb<ndim> &other) const {
+      double m = axisSeparation(other, 0);
+      for (unsigned i = 1; i < ndim; ++i) {
+        m = std::max(m, axisSeparation(other, i));
+      }
+      return m;
+    }
+
+    template<unsigned ndim>
+    bool aabb<ndim>::intersects(const aabb<ndim> &other) const {
+      return maxAxisSeparation(other) <= 0.0;
+    }
+ 
+    template<unsigned ndim>
+    bool aabb<ndim>::intersects(const sphere<ndim> &s) const {
+      double r = 0.0;
+      for (unsigned i = 0; i < ndim; ++i) {
+        double t = fabs(s.C[i] - pos[i]) - extent[i]; if (t > 0.0) r += t*t;
+      }
+      return r <= s.r*s.r;
+    }
+
+    template<unsigned ndim>
+    bool aabb<ndim>::intersects(const plane<ndim> &plane) const {
+      double d1 = fabs(distance(plane, pos));
+      double d2 = dot(abs(plane.N), extent);
+      return d1 <= d2;
+    }
+
+    template<unsigned ndim>
+    bool aabb<ndim>::intersects(const linesegment<ndim> &ls) const {
+      return intersectsLineSegment(ls.v1, ls.v2);
+    }
+
+    template<unsigned ndim>
+    std::pair<double, double> aabb<ndim>::rangeInDirection(const carve::geom::vector<ndim> &v) const {
+      double d1 = dot(v, pos);
+      double d2 = dot(abs(v), extent);
+
+      return std::make_pair(d1 - d2, d1 + d2);
+    }
+
+    template<unsigned ndim>
+    typename aabb<ndim>::vector_t aabb<ndim>::min() const { return pos - extent; }
+
+    template<unsigned ndim>
+    typename aabb<ndim>::vector_t aabb<ndim>::mid() const { return pos; }
+
+    template<unsigned ndim>
+    typename aabb<ndim>::vector_t aabb<ndim>::max() const { return pos + extent; }
+
+    template<unsigned ndim>
+    double aabb<ndim>::min(unsigned dim) const { return pos.v[dim] - extent.v[dim]; }
+
+    template<unsigned ndim>
+    double aabb<ndim>::mid(unsigned dim) const { return pos.v[dim]; }
+
+    template<unsigned ndim>
+    double aabb<ndim>::max(unsigned dim) const { return pos.v[dim] + extent.v[dim]; }
+
+    template<unsigned ndim>
+    double aabb<ndim>::volume() const {
+      double v = 1.0;
+      for (size_t dim = 0; dim < ndim; ++dim) { v *= 2.0 * extent.v[dim]; }
+      return v;
+    }
+
+    template<unsigned ndim>
+    int aabb<ndim>::compareAxis(const axis_pos &ap) const {
+      double p = ap.pos - pos[ap.axis];
+      if (p > extent[ap.axis]) return -1;
+      if (p < -extent[ap.axis]) return +1;
+      return 0;
+    }
+
+    template<unsigned ndim>
+    void aabb<ndim>::constrainMax(const axis_pos &ap) {
+      if (pos[ap.axis] + extent[ap.axis] > ap.pos) {
+        double min = std::min(ap.pos, pos[ap.axis] - extent[ap.axis]);
+        pos[ap.axis] = (min + ap.pos) / 2.0;
+        extent[ap.axis] = ap.pos - pos[ap.axis];
+      }
+    }
+
+    template<unsigned ndim>
+    void aabb<ndim>::constrainMin(const axis_pos &ap) {
+      if (pos[ap.axis] - extent[ap.axis] < ap.pos) {
+        double max = std::max(ap.pos, pos[ap.axis] + extent[ap.axis]);
+        pos[ap.axis] = (ap.pos + max) / 2.0;
+        extent[ap.axis] = pos[ap.axis] - ap.pos;
+      }
+    }
+
+    template<unsigned ndim>
+    aabb<ndim> aabb<ndim>::getAABB() const {
+      return *this;
+    }
+
+    template<unsigned ndim>
+    aabb<ndim>::aabb(const vector_t &_pos,
+                     const vector_t &_extent) : pos(_pos), extent(_extent) {
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t, typename adapt_t>
+    aabb<ndim>::aabb(iter_t begin, iter_t end, adapt_t adapt) {
+      fit(begin, end, adapt);
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    aabb<ndim>::aabb(iter_t begin, iter_t end) {
+      fit(begin, end);
+    }
+
+    template<unsigned ndim>
+    aabb<ndim>::aabb(const aabb<ndim> &a, const aabb<ndim> &b) {
+      fit(a, b);
+    }
+
+    template<unsigned ndim>
+    bool operator==(const aabb<ndim> &a, const aabb<ndim> &b) {
+      return a.pos == b.pos && a.extent == b.extent;
+    }
+
+    template<unsigned ndim>
+    bool operator!=(const aabb<ndim> &a, const aabb<ndim> &b) {
+      return a.pos != b.pos || a.extent != b.extent;
+    }
+
+    template<unsigned ndim>
+    std::ostream &operator<<(std::ostream &o, const aabb<ndim> &a) {
+      o << (a.pos - a.extent) << "--" << (a.pos + a.extent);
+      return o;
+    }
+
+    template<>
+    inline bool aabb<3>::intersects(const ray<3> &ray) const {
+      vector<3> t = pos - ray.v;
+      double r;
+
+      //l.cross(x-axis)?
+      r = extent.y * fabs(ray.D.z) + extent.z * fabs(ray.D.y);
+      if (fabs(t.y * ray.D.z - t.z * ray.D.y) > r) return false;
+
+      //ray.D.cross(y-axis)?
+      r = extent.x * fabs(ray.D.z) + extent.z * fabs(ray.D.x);
+      if (fabs(t.z * ray.D.x - t.x * ray.D.z) > r) return false;
+
+      //ray.D.cross(z-axis)?
+      r = extent.x*fabs(ray.D.y) + extent.y*fabs(ray.D.x);
+      if (fabs(t.x * ray.D.y - t.y * ray.D.x) > r) return false;
+
+      return true;
+    }
+
+    template<>
+    inline bool aabb<3>::intersectsLineSegment(const vector<3> &v1, const vector<3> &v2) const {
+      vector<3> half_length = 0.5 * (v2 - v1);
+      vector<3> t = pos - half_length - v1;
+      double r;
+
+      //do any of the principal axes form a separating axis?
+      if(fabs(t.x) > extent.x + fabs(half_length.x)) return false;
+      if(fabs(t.y) > extent.y + fabs(half_length.y)) return false;
+      if(fabs(t.z) > extent.z + fabs(half_length.z)) return false;
+
+      // NOTE: Since the separating axis is perpendicular to the line in
+      // these last four cases, the line does not contribute to the
+      // projection.
+
+      //line.cross(x-axis)?
+      r = extent.y * fabs(half_length.z) + extent.z * fabs(half_length.y);
+      if (fabs(t.y * half_length.z - t.z * half_length.y) > r) return false;
+
+      //half_length.cross(y-axis)?
+      r = extent.x * fabs(half_length.z) + extent.z * fabs(half_length.x);
+      if (fabs(t.z * half_length.x - t.x * half_length.z) > r) return false;
+
+      //half_length.cross(z-axis)?
+      r = extent.x*fabs(half_length.y) + extent.y*fabs(half_length.x);
+      if (fabs(t.x * half_length.y - t.y * half_length.x) > r) return false;
+
+      return true;
+    }
+
+    template<int Ax, int Ay, int Az, int c>
+    static inline bool intersectsTriangle_axisTest_3(const aabb<3> &aabb, const tri<3> &tri) {
+      const int d = (c+1) % 3, e = (c+2) % 3;
+      const vector<3> a = cross(VECTOR(Ax, Ay, Az), tri.v[d] - tri.v[c]);
+      double p1 = dot(a, tri.v[c]), p2 = dot(a, tri.v[e]);
+      if (p1 > p2) std::swap(p1, p2);
+      const double r = dot(abs(a), aabb.extent);
+      return !(p1 > r || p2 < -r);
+    }
+
+    template<int c>
+    static inline bool intersectsTriangle_axisTest_2(const aabb<3> &aabb, const tri<3> &tri) {
+      double vmin = std::min(std::min(tri.v[0][c], tri.v[1][c]), tri.v[2][c]),
+             vmax = std::max(std::max(tri.v[0][c], tri.v[1][c]), tri.v[2][c]);
+      return !(vmin > aabb.extent[c] || vmax < -aabb.extent[c]);
+    }
+
+    static inline bool intersectsTriangle_axisTest_1(const aabb<3> &aabb, const tri<3> &tri) {
+      vector<3> n = cross(tri.v[1] - tri.v[0], tri.v[2] - tri.v[0]);
+      double d1 = fabs(dot(n, tri.v[0]));
+      double d2 = dot(abs(n), aabb.extent);
+      return d1 <= d2;
+    }
+
+    template<>
+    inline bool aabb<3>::intersects(tri<3> tri) const {
+      tri.v[0] -= pos;
+      tri.v[1] -= pos;
+      tri.v[2] -= pos;
+
+      if (!intersectsTriangle_axisTest_2<0>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_2<1>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_2<2>(*this, tri)) return false;
+
+      if (!intersectsTriangle_axisTest_3<1,0,0,0>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_3<1,0,0,1>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_3<1,0,0,2>(*this, tri)) return false;
+                                                          
+      if (!intersectsTriangle_axisTest_3<0,1,0,0>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_3<0,1,0,1>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_3<0,1,0,2>(*this, tri)) return false;
+                                                          
+      if (!intersectsTriangle_axisTest_3<0,0,1,0>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_3<0,0,1,1>(*this, tri)) return false;
+      if (!intersectsTriangle_axisTest_3<0,0,1,2>(*this, tri)) return false;
+
+      if (!intersectsTriangle_axisTest_1(*this, tri)) return false;
+
+      return true;
+    }
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/carve.hpp b/extern/carve/include/carve/carve.hpp
new file mode 100644
index 00000000000..90ca6b4977b
--- /dev/null
+++ b/extern/carve/include/carve/carve.hpp
@@ -0,0 +1,238 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#if defined(CMAKE_BUILD)
+#  include <carve/config.h>
+#elif defined(XCODE_BUILD)
+#  include <carve/xcode_config.h>
+#elif defined(_MSC_VER)
+#  include <carve/vcpp_config.h>
+#else
+#  include <carve/config.h>
+#endif
+
+#if defined(WIN32)
+#  include <carve/win32.h>
+#elif defined(__GNUC__)
+#  include <carve/gnu_cxx.h>
+#endif
+
+#if defined(CARVE_SYSTEM_BOOST)
+#  define BOOST_INCLUDE(x) <boost/x>
+#else
+#  define BOOST_INCLUDE(x) <carve/external/boost/x>
+#endif
+
+#include <math.h>
+
+#include <string>
+#include <set>
+#include <map>
+#include <vector>
+#include <list>
+#include <sstream>
+#include <iomanip>
+
+#include <carve/collection.hpp>
+
+#include <carve/util.hpp>
+
+#include <stdarg.h>
+
+#define STR(x) #x
+#define XSTR(x) STR(x)
+
+/**
+ * \brief Top level Carve namespace.
+ */
+namespace carve {
+  static struct noinit_t {} NOINIT;
+
+  inline std::string fmtstring(const char *fmt, ...);
+
+  /**
+   * \brief Base class for all Carve exceptions.
+   */
+  struct exception {
+  private:
+    mutable std::string err;
+    mutable std::ostringstream accum;
+
+  public:
+    exception(const std::string &e) : err(e), accum() { }
+    exception() : err(), accum() { }
+    exception(const exception &e) : err(e.str()), accum() { }
+    exception &operator=(const exception &e) {
+      if (this != &e) {
+        err = e.str();
+        accum.str("");
+      }
+      return *this;
+    }
+
+    const std::string &str() const {
+      if (accum.str().size() > 0) {
+        err += accum.str();
+        accum.str("");
+      }
+      return err;
+    }
+
+    template<typename T>
+    exception &operator<<(const T &t) {
+      accum << t;
+      return *this;
+    }
+  };
+
+  template<typename iter_t, typename order_t = std::less<typename std::iterator_traits<iter_t>::value_type > >
+  struct index_sort {
+    iter_t base;
+    order_t order;
+    index_sort(const iter_t &_base) : base(_base), order() { }
+    index_sort(const iter_t &_base, const order_t &_order) : base(_base), order(_order) { }
+    template<typename U>
+    bool operator()(const U &a, const U &b) {
+      return order(*(base + a), *(base + b));
+    }
+  };
+
+  template<typename iter_t, typename order_t>
+  index_sort<iter_t, order_t> make_index_sort(const iter_t &base, const order_t &order) {
+    return index_sort<iter_t, order_t>(base, order);
+  }
+
+  template<typename iter_t>
+  index_sort<iter_t> make_index_sort(const iter_t &base) {
+    return index_sort<iter_t>(base);
+  }
+
+
+  enum RayIntersectionClass {
+    RR_DEGENERATE = -2,
+    RR_PARALLEL = -1,
+    RR_NO_INTERSECTION = 0,
+    RR_INTERSECTION = 1
+  };
+
+  enum LineIntersectionClass {
+    COLINEAR        = -1,
+    NO_INTERSECTION = 0,
+    INTERSECTION_LL = 1,
+    INTERSECTION_PL = 2,
+    INTERSECTION_LP = 3,
+    INTERSECTION_PP = 4
+  };
+
+  enum PointClass {
+    POINT_UNK = -2,
+    POINT_OUT = -1,
+    POINT_ON = 0,
+    POINT_IN = 1,
+    POINT_VERTEX = 2,
+    POINT_EDGE = 3
+  };
+
+  enum IntersectionClass {
+    INTERSECT_BAD = -1,
+    INTERSECT_NONE = 0,
+    INTERSECT_FACE = 1,
+    INTERSECT_VERTEX = 2,
+    INTERSECT_EDGE = 3,
+    INTERSECT_PLANE = 4,
+  };
+
+
+
+  extern double EPSILON;
+  extern double EPSILON2;
+
+  static inline void setEpsilon(double ep) { EPSILON = ep; EPSILON2 = ep * ep; }
+
+
+
+  template<typename T>
+  struct identity_t {
+    typedef T argument_type;
+    typedef T result_type;
+    const T &operator()(const T &t) const { return t; }
+  };
+
+
+
+  template<typename iter_t>
+  inline bool is_sorted(iter_t first, iter_t last) {
+    if (first == last) return true;
+
+    iter_t iter = first;
+    iter_t next = first; ++next;
+    for (; next != last; iter = next, ++next) {
+      if (*next < *iter) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+
+
+  template<typename iter_t,
+           typename pred_t>
+  inline bool is_sorted(iter_t first, iter_t last, pred_t pred) {
+    if (first == last) return true;
+
+    iter_t iter = first;
+    iter_t next = first; ++next;
+    for (; next != last; iter = next, ++next) {
+      if (pred(*next, *iter)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+
+
+  inline double rangeSeparation(const std::pair<double, double> &a,
+                                const std::pair<double, double> &b) {
+    if (a.second < b.first) {
+      return b.first - a.second;
+    } else if (b.second < a.first) {
+      return a.first - b.second;
+    } else {
+      return 0.0;
+    }
+  }
+}
+
+
+#if defined(_MSC_VER)
+#  define MACRO_BEGIN do {
+#  define MACRO_END   __pragma(warning(push)) __pragma(warning(disable:4127)) } while(0) __pragma(warning(pop))
+#else
+#  define MACRO_BEGIN do {
+#  define MACRO_END   } while(0)
+#endif
+
+#if !defined(CARVE_NODEBUG)
+#  define CARVE_ASSERT(x) MACRO_BEGIN if (!(x)) throw carve::exception() << __FILE__ << ":" << __LINE__ << "  " << #x; MACRO_END
+#else
+#  define CARVE_ASSERT(X)
+#endif
+
+#define CARVE_FAIL(x) MACRO_BEGIN throw carve::exception() << __FILE__ << ":" << __LINE__ << "  " << #x; MACRO_END
diff --git a/extern/carve/include/carve/cbrt.h b/extern/carve/include/carve/cbrt.h
new file mode 100644
index 00000000000..aeceab01426
--- /dev/null
+++ b/extern/carve/include/carve/cbrt.h
@@ -0,0 +1,93 @@
+// N.B. only appropriate for IEEE doubles.
+// Cube root implementation obtained from code with the following notice:
+
+/* @(#)s_cbrt.c 1.3 95/01/18 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice 
+ * is preserved.
+ * ====================================================
+ *
+ */
+
+/* Sometimes it's necessary to define __LITTLE_ENDIAN explicitly
+   but these catch some common cases. */
+
+#if defined(i386) || defined(i486) || \
+	defined(intel) || defined(x86) || defined(i86pc) || \
+	defined(__alpha) || defined(__osf__)
+#define __LITTLE_ENDIAN
+#endif
+
+#ifdef __LITTLE_ENDIAN
+#define __HI(x) *(1+(int*)&x)
+#define __LO(x) *(int*)&x
+#define __HIp(x) *(1+(int*)x)
+#define __LOp(x) *(int*)x
+#else
+#define __HI(x) *(int*)&x
+#define __LO(x) *(1+(int*)&x)
+#define __HIp(x) *(int*)x
+#define __LOp(x) *(1+(int*)x)
+#endif
+
+/* cbrt(x)
+ * Return cube root of x
+ */
+
+inline double cbrt(double x) {
+
+  static const unsigned 
+    B1 = 715094163, /* B1 = (682-0.03306235651)*2**20 */
+    B2 = 696219795; /* B2 = (664-0.03306235651)*2**20 */
+  static const double
+    C =  5.42857142857142815906e-01, /* 19/35     = 0x3FE15F15, 0xF15F15F1 */
+    D = -7.05306122448979611050e-01, /* -864/1225 = 0xBFE691DE, 0x2532C834 */
+    E =  1.41428571428571436819e+00, /* 99/70     = 0x3FF6A0EA, 0x0EA0EA0F */
+    F =  1.60714285714285720630e+00, /* 45/28     = 0x3FF9B6DB, 0x6DB6DB6E */
+    G =  3.57142857142857150787e-01; /* 5/14      = 0x3FD6DB6D, 0xB6DB6DB7 */
+
+  int	hx;
+  double r,s,t=0.0,w;
+  unsigned sign;
+
+  hx = __HI(x);		/* high word of x */
+  sign=hx&0x80000000; 		/* sign= sign(x) */
+  hx  ^=sign;
+  if(hx>=0x7ff00000) return(x+x); /* cbrt(NaN,INF) is itself */
+  if((hx|__LO(x))==0) 
+    return(x);		/* cbrt(0) is itself */
+
+  __HI(x) = hx;	/* x <- |x| */
+  /* rough cbrt to 5 bits */
+  if(hx<0x00100000) 		/* subnormal number */
+    {__HI(t)=0x43500000; 		/* set t= 2**54 */
+    t*=x; __HI(t)=__HI(t)/3+B2;
+    }
+  else
+    __HI(t)=hx/3+B1;	
+  
+
+  /* new cbrt to 23 bits, may be implemented in single precision */
+  r=t*t/x;
+  s=C+r*t;
+  t*=G+F/(s+E+D/s);	
+
+  /* chopped to 20 bits and make it larger than cbrt(x) */ 
+  __LO(t)=0; __HI(t)+=0x00000001;
+
+  /* one step newton iteration to 53 bits with error less than 0.667 ulps */
+  s=t*t;		/* t*t is exact */
+  r=x/s;
+  w=t+t;
+  r=(r-t)/(w+r);	/* r-s is exact */
+  t=t+t*r;
+
+  /* retore the sign bit */
+  __HI(t) |= sign;
+  return(t);
+}
diff --git a/extern/carve/include/carve/classification.hpp b/extern/carve/include/carve/classification.hpp
new file mode 100644
index 00000000000..7df86db7823
--- /dev/null
+++ b/extern/carve/include/carve/classification.hpp
@@ -0,0 +1,115 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/collection_types.hpp>
+
+namespace carve {
+  namespace csg {
+
+    enum FaceClass {
+      FACE_UNCLASSIFIED = -3,
+      FACE_ON_ORIENT_OUT = -2,
+      FACE_OUT = -1,
+      FACE_ON = 0,
+      FACE_IN = +1,
+      FACE_ON_ORIENT_IN = +2
+    };
+
+    enum FaceClassBit {
+      FACE_ON_ORIENT_OUT_BIT = 0x01,
+      FACE_OUT_BIT           = 0x02,
+      FACE_IN_BIT            = 0x04,
+      FACE_ON_ORIENT_IN_BIT  = 0x08,
+
+      FACE_ANY_BIT           = 0x0f,
+      FACE_ON_BIT            = 0x09,
+      FACE_NOT_ON_BIT        = 0x06
+    };
+
+    static inline FaceClass class_bit_to_class(unsigned i) {
+      if (i & FACE_ON_ORIENT_OUT_BIT) return FACE_ON_ORIENT_OUT;
+      if (i & FACE_OUT_BIT) return FACE_OUT;
+      if (i & FACE_IN_BIT) return FACE_IN;
+      if (i & FACE_ON_ORIENT_IN_BIT) return FACE_ON_ORIENT_IN;
+      return FACE_UNCLASSIFIED;
+    }
+
+    static inline unsigned class_to_class_bit(FaceClass f) {
+      switch (f) {
+      case FACE_ON_ORIENT_OUT: return FACE_ON_ORIENT_OUT_BIT;
+      case FACE_OUT: return FACE_OUT_BIT;
+      case FACE_ON: return FACE_ON_BIT;
+      case FACE_IN: return FACE_IN_BIT;
+      case FACE_ON_ORIENT_IN: return FACE_ON_ORIENT_IN_BIT;
+      case FACE_UNCLASSIFIED: return FACE_ANY_BIT;
+      default: return 0;
+      }
+    }
+
+    enum EdgeClass {
+      EDGE_UNK = -2,
+      EDGE_OUT = -1,
+      EDGE_ON = 0,
+      EDGE_IN = 1
+    };
+
+
+
+    const char *ENUM(FaceClass f);
+    const char *ENUM(PointClass p);
+
+
+
+    struct ClassificationInfo {
+      const carve::mesh::Mesh<3> *intersected_mesh;
+      FaceClass classification;
+
+      ClassificationInfo() : intersected_mesh(NULL), classification(FACE_UNCLASSIFIED) { }
+      ClassificationInfo(const carve::mesh::Mesh<3> *_intersected_mesh,
+                         FaceClass _classification) :
+          intersected_mesh(_intersected_mesh),
+          classification(_classification) {
+      }
+      bool intersectedMeshIsClosed() const {
+        return intersected_mesh->isClosed();
+      }
+    };
+
+
+
+    struct EC2 {
+      EdgeClass cls[2];
+      EC2() { cls[0] = cls[1] = EDGE_UNK; }
+      EC2(EdgeClass a, EdgeClass b) { cls[0] = a; cls[1] = b; }
+    };
+
+    struct PC2 {
+      PointClass cls[2];
+      PC2() { cls[0] = cls[1] = POINT_UNK; }
+      PC2(PointClass a, PointClass b) { cls[0] = a; cls[1] = b; }
+    };
+
+    typedef std::unordered_map<std::pair<const carve::mesh::MeshSet<3>::vertex_t *, const carve::mesh::MeshSet<3>::vertex_t *>,
+                               EC2> EdgeClassification;
+
+    typedef std::unordered_map<const carve::mesh::Vertex<3> *, PC2> VertexClassification;
+
+  }
+}
diff --git a/extern/carve/include/carve/collection.hpp b/extern/carve/include/carve/collection.hpp
new file mode 100644
index 00000000000..ace63d174f6
--- /dev/null
+++ b/extern/carve/include/carve/collection.hpp
@@ -0,0 +1,51 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/collection/unordered.hpp>
+
+namespace carve {
+
+  template<typename set_t>
+  class set_insert_iterator : public std::iterator<std::output_iterator_tag, void, void, void, void> {
+
+  protected:
+    set_t *set;
+  public:
+
+    set_insert_iterator(set_t &s) : set(&s) {
+    }
+
+    set_insert_iterator &
+    operator=(typename set_t::const_reference value) {
+      set->insert(value);
+      return *this;
+    }
+
+    set_insert_iterator &operator*() { return *this; }
+    set_insert_iterator &operator++() { return *this; }
+    set_insert_iterator &operator++(int) { return *this; }
+  };
+
+  template<typename set_t>
+  inline set_insert_iterator<set_t>
+  set_inserter(set_t &s) {
+    return set_insert_iterator<set_t>(s);
+  }
+
+}
diff --git a/extern/carve/include/carve/collection/unordered.hpp b/extern/carve/include/carve/collection/unordered.hpp
new file mode 100644
index 00000000000..494a1ca4013
--- /dev/null
+++ b/extern/carve/include/carve/collection/unordered.hpp
@@ -0,0 +1,43 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#if defined(HAVE_STD_UNORDERED_COLLECTIONS)
+
+#  include <carve/collection/unordered/std_impl.hpp>
+
+#elif defined(HAVE_TR1_UNORDERED_COLLECTIONS)
+
+#  include <carve/collection/unordered/tr1_impl.hpp>
+
+#elif defined(HAVE_BOOST_UNORDERED_COLLECTIONS)
+
+#  include <carve/collection/unordered/boost_impl.hpp>
+
+#elif defined(HAVE_LIBSTDCPP_UNORDERED_COLLECTIONS)
+
+#  include <carve/collection/unordered/libstdcpp_impl.hpp>
+
+#elif defined(_MSC_VER) && _MSC_VER >= 1300
+
+#  include <carve/collection/unordered/vcpp_impl.hpp>
+
+#else
+
+#  include <carve/collection/unordered/fallback_impl.hpp>
+
+#endif
diff --git a/extern/carve/include/carve/collection/unordered/boost_impl.hpp b/extern/carve/include/carve/collection/unordered/boost_impl.hpp
new file mode 100644
index 00000000000..96b1407e9eb
--- /dev/null
+++ b/extern/carve/include/carve/collection/unordered/boost_impl.hpp
@@ -0,0 +1,45 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include BOOST_INCLUDE(unordered_set.hpp)
+#include BOOST_INCLUDE(unordered_map.hpp)
+
+#include <functional>
+
+namespace std {
+  template <typename Key, typename T, typename Hash = boost::hash<Key>,
+            typename Pred = std::equal_to<Key> >
+  class unordered_map : public boost::unordered_map<Key, T, Hash, Pred> {
+
+  public:
+    typedef T data_type;
+  };
+
+  template <typename Key, typename T, typename Hash = boost::hash<Key>,
+            typename Pred = std::equal_to<Key> >
+  class unordered_multimap : public boost::unordered_multimap<Key, T, Hash, Pred> {
+  };
+
+  template <typename Value, typename Hash = boost::hash<Value>,
+            typename Pred = std::equal_to<Value> >
+  class unordered_set : public boost::unordered_set<Value, Hash, Pred> {
+  };
+}
+
+#undef UNORDERED_COLLECTIONS_SUPPORT_RESIZE
diff --git a/extern/carve/include/carve/collection/unordered/fallback_impl.hpp b/extern/carve/include/carve/collection/unordered/fallback_impl.hpp
new file mode 100644
index 00000000000..70422b2a215
--- /dev/null
+++ b/extern/carve/include/carve/collection/unordered/fallback_impl.hpp
@@ -0,0 +1,40 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <set>
+#include <map>
+
+namespace std {
+
+  template<typename K, typename T, typename H = int>
+  class unordered_map : public std::map<K, T> {
+    typedef std::map<K, T> super;
+  public:
+    typedef T data_type;
+  };
+
+  template<typename K, typename H = int>
+  class unordered_set : public std::set<K> {
+    typedef std::set<K> super;
+  public:
+  };
+
+}
+
+#undef UNORDERED_COLLECTIONS_SUPPORT_RESIZE
diff --git a/extern/carve/include/carve/collection/unordered/libstdcpp_impl.hpp b/extern/carve/include/carve/collection/unordered/libstdcpp_impl.hpp
new file mode 100644
index 00000000000..e1ad430709d
--- /dev/null
+++ b/extern/carve/include/carve/collection/unordered/libstdcpp_impl.hpp
@@ -0,0 +1,61 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#include <ext/hash_map>
+#include <ext/hash_set>
+
+namespace __gnu_cxx {
+  template <typename T>
+  struct hash<T *> : public std::unary_function<T *, size_t> {
+    size_t operator()(T *v) const {
+      size_t x = (size_t)(v);
+      return x + (x>>3);
+    }
+  };
+
+  template <typename A, typename B>
+  struct hash<std::pair<A, B> > : public std::unary_function<std::pair<A, B>, size_t> {
+    size_t operator()(const std::pair<A, B> &v) const {
+      std::size_t seed = 0;
+
+      seed ^= hash<A>()(v.first);
+      seed ^= hash<B>()(v.second) + (seed<<6) + (seed>>2);
+
+      return seed;
+    }
+  };
+}
+
+namespace std {
+
+  template<typename K, typename V, typename H = __gnu_cxx::hash<K> >
+  class unordered_map : public __gnu_cxx::hash_map<K, V, H> {
+    typedef __gnu_cxx::hash_map<K, V, H> super;
+  public:
+    typedef typename super::mapped_type data_type;
+  };
+
+  template<typename K, typename H = __gnu_cxx::hash<K> >
+  class unordered_set : public __gnu_cxx::hash_set<K, H> {
+    typedef __gnu_cxx::hash_set<K, H> super;
+  public:
+  };
+
+}
+
+#define UNORDERED_COLLECTIONS_SUPPORT_RESIZE 1
diff --git a/extern/carve/include/carve/collection/unordered/std_impl.hpp b/extern/carve/include/carve/collection/unordered/std_impl.hpp
new file mode 100644
index 00000000000..68a3f122e86
--- /dev/null
+++ b/extern/carve/include/carve/collection/unordered/std_impl.hpp
@@ -0,0 +1,23 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <unordered_map>
+#include <unordered_set>
+
+#undef UNORDERED_COLLECTIONS_SUPPORT_RESIZE
diff --git a/extern/carve/include/carve/collection/unordered/tr1_impl.hpp b/extern/carve/include/carve/collection/unordered/tr1_impl.hpp
new file mode 100644
index 00000000000..2c7f39f6a74
--- /dev/null
+++ b/extern/carve/include/carve/collection/unordered/tr1_impl.hpp
@@ -0,0 +1,58 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <tr1/unordered_map>
+#include <tr1/unordered_set>
+#include <tr1/functional>
+
+namespace std {
+  namespace tr1 {
+    template <typename A, typename B>
+    struct hash<std::pair<A, B> > : public std::unary_function<std::pair<A, B>, size_t> {
+      size_t operator()(const std::pair<A, B> &v) const {
+        std::size_t seed = 0;
+
+        seed ^= hash<A>()(v.first);
+        seed ^= hash<B>()(v.second) + (seed<<6) + (seed>>2);
+
+        return seed;
+      }
+    };
+  }
+
+
+
+  template <typename Key, typename T,
+            typename Hash = tr1::hash<Key>,
+            typename Pred = std::equal_to<Key> >
+  class unordered_map : public std::tr1::unordered_map<Key, T, Hash, Pred> {
+  public:
+    typedef T data_type;
+  };
+
+  template <typename Value,
+            typename Hash = tr1::hash<Value>,
+            typename Pred = std::equal_to<Value> >
+  class unordered_set : public std::tr1::unordered_set<Value, Hash, Pred> {
+  public:
+  };
+
+}
+
+#undef UNORDERED_COLLECTIONS_SUPPORT_RESIZE
diff --git a/extern/carve/include/carve/collection/unordered/vcpp_impl.hpp b/extern/carve/include/carve/collection/unordered/vcpp_impl.hpp
new file mode 100644
index 00000000000..825edad1433
--- /dev/null
+++ b/extern/carve/include/carve/collection/unordered/vcpp_impl.hpp
@@ -0,0 +1,65 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <hash_map>
+#include <hash_set>
+
+namespace std {
+
+  namespace {
+
+    template<class Value, class Hash> class hash_traits {
+      Hash hash_value;
+      std::less<Value> comp;
+    public:
+      enum {
+        bucket_size = 4,
+        min_buckets = 8
+      };
+      // hash _Keyval to size_t value
+      size_t operator()(const Value& v) const {
+        return ((size_t)hash_value(v));
+      }
+      // test if _Keyval1 ordered before _Keyval2
+      bool operator()(const Value& v1, const Value& v2) const {
+        return (comp(v1, v2));
+      }
+    };
+
+  }
+
+  template <typename Key, typename T, typename Hash = stdext::hash_compare<Key, less<Key> >, typename Pred = std::equal_to<Key> >
+  class unordered_map 
+    : public stdext::hash_map<Key, T, hash_traits<Key, Hash> > {
+    typedef stdext::hash_map<Key, T, hash_traits<Key, Hash> > super;
+  public:
+    unordered_map() : super() {}
+  };
+
+  template <typename Value, typename Hash = stdext::hash_compare<Key, less<Key> >, typename Pred = std::equal_to<Value> >
+  class unordered_set
+    : public stdext::hash_set<Value, hash_traits<Value, Hash> > {
+    typedef stdext::hash_set<Value, hash_traits<Value, Hash> > super;
+  public:
+    unordered_set() : super() {}
+  };
+
+}
+
+#undef UNORDERED_COLLECTIONS_SUPPORT_RESIZE
diff --git a/extern/carve/include/carve/collection_types.hpp b/extern/carve/include/carve/collection_types.hpp
new file mode 100644
index 00000000000..997d5811801
--- /dev/null
+++ b/extern/carve/include/carve/collection_types.hpp
@@ -0,0 +1,63 @@
+
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/mesh.hpp>
+
+namespace carve {
+  namespace csg {
+
+    typedef std::pair<
+      carve::mesh::MeshSet<3>::vertex_t *,
+      carve::mesh::MeshSet<3>::vertex_t *> V2;
+
+    typedef std::pair<
+      carve::mesh::MeshSet<3>::face_t *,
+      carve::mesh::MeshSet<3>::face_t *> F2;
+
+    static inline V2 ordered_edge(
+      carve::mesh::MeshSet<3>::vertex_t *a,
+      carve::mesh::MeshSet<3>::vertex_t *b) {
+      return V2(std::min(a, b), std::max(a, b));
+    }
+
+    static inline V2 flip(const V2 &v) {
+      return V2(v.second, v.first);
+    }
+
+    // include/carve/csg.hpp include/carve/faceloop.hpp
+    // lib/intersect.cpp lib/intersect_classify_common_impl.hpp
+    // lib/intersect_classify_edge.cpp
+    // lib/intersect_classify_group.cpp
+    // lib/intersect_classify_simple.cpp
+    // lib/intersect_face_division.cpp lib/intersect_group.cpp
+    // lib/intersect_half_classify_group.cpp
+    typedef std::unordered_set<V2> V2Set;
+
+    // include/carve/csg.hpp include/carve/polyhedron_decl.hpp
+    // lib/csg_collector.cpp lib/intersect.cpp
+    // lib/intersect_common.hpp lib/intersect_face_division.cpp
+    // lib/polyhedron.cpp
+    typedef std::unordered_map<
+      carve::mesh::MeshSet<3>::vertex_t *,
+      carve::mesh::MeshSet<3>::vertex_t *> VVMap;
+  }
+}
diff --git a/extern/carve/include/carve/colour.hpp b/extern/carve/include/carve/colour.hpp
new file mode 100644
index 00000000000..420f8f7e13b
--- /dev/null
+++ b/extern/carve/include/carve/colour.hpp
@@ -0,0 +1,47 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/geom.hpp>
+
+namespace carve {
+  namespace colour {
+    static inline void HSV2RGB(float H, float S, float V, float &r, float &g, float &b) {
+      H = 6.0f * H;
+      if (S < 5.0e-6) {
+        r = g = b = V; return;
+      } else {
+        int i = (int)H;
+        float f = H - i;
+        float p1 = V * (1.0f - S);
+        float p2 = V * (1.0f - S * f);
+        float p3 = V * (1.0f - S * (1.0f - f));
+        switch (i) {
+        case 0:  r = V;  g = p3; b = p1; return;
+        case 1:  r = p2; g = V;  b = p1; return;
+        case 2:  r = p1; g = V;  b = p3; return;
+        case 3:  r = p1; g = p2; b = V;  return;
+        case 4:  r = p3; g = p1; b = V;  return;
+        case 5:  r = V;  g = p1; b = p2; return;
+        }
+      }
+      r = g = b = 0.0;
+    }
+  }
+}
diff --git a/extern/carve/include/carve/config.h b/extern/carve/include/carve/config.h
new file mode 100644
index 00000000000..fdae2d2843f
--- /dev/null
+++ b/extern/carve/include/carve/config.h
@@ -0,0 +1,12 @@
+#define CARVE_VERSION "2.0.0a"
+
+#undef CARVE_DEBUG
+#undef CARVE_DEBUG_WRITE_PLY_DATA
+
+#if defined(__GNUC__)
+#  if !defined(HAVE_BOOST_UNORDERED_COLLECTIONS)
+#    define HAVE_TR1_UNORDERED_COLLECTIONS
+#  endif
+
+#  define HAVE_STDINT_H
+#endif
diff --git a/extern/carve/include/carve/convex_hull.hpp b/extern/carve/include/carve/convex_hull.hpp
new file mode 100644
index 00000000000..bcb7c97e20f
--- /dev/null
+++ b/extern/carve/include/carve/convex_hull.hpp
@@ -0,0 +1,52 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <list>
+#include <vector>
+#include <algorithm>
+
+#include <carve/carve.hpp>
+
+#include <carve/geom2d.hpp>
+
+namespace carve {
+  namespace geom {
+    std::vector<int> convexHull(const std::vector<carve::geom2d::P2> &points);
+
+    template<typename project_t, typename polygon_container_t>
+    std::vector<int> convexHull(const project_t &project, const polygon_container_t &points) {
+      std::vector<carve::geom2d::P2> proj;
+      proj.reserve(points.size());
+      for (typename polygon_container_t::const_iterator i = points.begin(); i != points.end(); ++i) {
+        proj.push_back(project(*i));
+      }
+      return convexHull(proj);
+    }
+
+    template<typename project_t, typename iter_t>
+    std::vector<int> convexHull(const project_t &project, iter_t beg, iter_t end, size_t size_hint = 0) {
+      std::vector<carve::geom2d::P2> proj;
+      if (size_hint) proj.reserve(size_hint);
+      for (; beg != end; ++beg) {
+        proj.push_back(project(*beg));
+      }
+      return convexHull(proj);
+    }
+  }
+}
diff --git a/extern/carve/include/carve/csg.hpp b/extern/carve/include/carve/csg.hpp
new file mode 100644
index 00000000000..db32273a33c
--- /dev/null
+++ b/extern/carve/include/carve/csg.hpp
@@ -0,0 +1,498 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <list>
+#include <vector>
+#include <algorithm>
+
+#include <carve/carve.hpp>
+
+#include <carve/geom3d.hpp>
+
+#include <carve/mesh.hpp>
+
+#include <carve/collection_types.hpp>
+#include <carve/classification.hpp>
+#include <carve/iobj.hpp>
+#include <carve/faceloop.hpp>
+#include <carve/intersection.hpp>
+#include <carve/rtree.hpp>
+
+namespace carve {
+  namespace csg {
+
+    class VertexPool {
+      typedef carve::mesh::MeshSet<3>::vertex_t vertex_t;
+
+      const static unsigned blocksize = 1024;
+      typedef std::list<std::vector<vertex_t> > pool_t;
+      pool_t pool;
+    public:
+      void reset();
+      vertex_t *get(const vertex_t::vector_t &v = vertex_t::vector_t::ZERO());
+      bool inPool(vertex_t *v) const;
+
+      VertexPool();
+      ~VertexPool();
+    };
+
+
+
+    namespace detail {
+      struct Data;
+      class LoopEdges;
+    }
+
+    /** 
+     * \class CSG
+     * \brief The class responsible for the computation of CSG operations.
+     * 
+     */
+    class CSG {
+    private:
+
+    public:
+      typedef carve::mesh::MeshSet<3> meshset_t;
+
+      struct Hook {
+        /** 
+         * \class Hook
+         * \brief Provides API access to intermediate steps in CSG calculation.
+         * 
+         */
+        virtual void intersectionVertex(const meshset_t::vertex_t * /* vertex */,
+                                        const IObjPairSet & /* intersections */) {
+        }
+        virtual void processOutputFace(std::vector<meshset_t::face_t *> & /* faces */,
+                                       const meshset_t::face_t * /* orig_face */,
+                                       bool /* flipped */) {
+        }
+        virtual void resultFace(const meshset_t::face_t * /* new_face */,
+                                const meshset_t::face_t * /* orig_face */,
+                                bool /* flipped */) {
+        }
+
+        virtual ~Hook() {
+        }
+      };
+
+        /** 
+         * \class Hooks
+         * \brief Management of API hooks.
+         * 
+         */
+      class Hooks {
+      public:
+        enum {
+          RESULT_FACE_HOOK         = 0,
+          PROCESS_OUTPUT_FACE_HOOK = 1,
+          INTERSECTION_VERTEX_HOOK = 2,
+          HOOK_MAX                 = 3,
+
+          RESULT_FACE_BIT          = 0x0001,
+          PROCESS_OUTPUT_FACE_BIT  = 0x0002, 
+          INTERSECTION_VERTEX_BIT  = 0x0004
+       };
+
+        std::vector<std::list<Hook *> > hooks;
+
+        bool hasHook(unsigned hook_num);
+
+        void intersectionVertex(const meshset_t::vertex_t *vertex,
+                                const IObjPairSet &intersections);
+
+        void processOutputFace(std::vector<meshset_t::face_t *> &faces,
+                               const meshset_t::face_t *orig_face,
+                               bool flipped);
+
+        void resultFace(const meshset_t::face_t *new_face,
+                        const meshset_t::face_t *orig_face,
+                        bool flipped);
+
+        void registerHook(Hook *hook, unsigned hook_bits);
+        void unregisterHook(Hook *hook);
+
+        void reset();
+
+        Hooks();
+        ~Hooks();
+      };
+
+        /** 
+         * \class Collector
+         * \brief Base class for objects responsible for selecting result from which form the result polyhedron.
+         * 
+         */
+      class Collector {
+        Collector(const Collector &);
+        Collector &operator=(const Collector &);
+
+      protected:
+
+      public:
+        virtual void collect(FaceLoopGroup *group, CSG::Hooks &) =0;
+        virtual meshset_t *done(CSG::Hooks &) =0;
+
+        Collector() {}
+        virtual ~Collector() {}
+      };
+
+    private:
+      typedef carve::geom::RTreeNode<3, carve::mesh::Face<3> *> face_rtree_t;
+      typedef std::unordered_map<carve::mesh::Face<3> *, std::vector<carve::mesh::Face<3> *> > face_pairs_t;
+
+      /// The computed intersection data.
+      Intersections intersections;
+
+      /// A map from intersection point to a set of intersections
+      /// represented by pairs of intersection objects.
+      VertexIntersections vertex_intersections;
+
+      /// A pool from which temporary vertices are allocated. Also
+      /// provides testing for pool membership.
+      VertexPool vertex_pool;
+
+      void init();
+
+      void makeVertexIntersections();
+
+      void groupIntersections();
+
+      void _generateVertexVertexIntersections(carve::mesh::MeshSet<3>::vertex_t *va,
+                                              carve::mesh::MeshSet<3>::edge_t *eb);
+      void generateVertexVertexIntersections(carve::mesh::MeshSet<3>::face_t *a,
+                                             const std::vector<carve::mesh::MeshSet<3>::face_t *> &b);
+
+      void _generateVertexEdgeIntersections(carve::mesh::MeshSet<3>::vertex_t *va,
+                                            carve::mesh::MeshSet<3>::edge_t *eb);
+      void generateVertexEdgeIntersections(carve::mesh::MeshSet<3>::face_t *a,
+                                           const std::vector<carve::mesh::MeshSet<3>::face_t *> &b);
+
+      void _generateEdgeEdgeIntersections(carve::mesh::MeshSet<3>::edge_t *ea,
+                                          carve::mesh::MeshSet<3>::edge_t *eb);
+      void generateEdgeEdgeIntersections(carve::mesh::MeshSet<3>::face_t *a,
+                                         const std::vector<carve::mesh::MeshSet<3>::face_t *> &b);
+
+      void _generateVertexFaceIntersections(carve::mesh::MeshSet<3>::face_t *fa,
+                                            carve::mesh::MeshSet<3>::edge_t *eb);
+      void generateVertexFaceIntersections(carve::mesh::MeshSet<3>::face_t *a,
+                                           const std::vector<carve::mesh::MeshSet<3>::face_t *> &b);
+
+      void _generateEdgeFaceIntersections(carve::mesh::MeshSet<3>::face_t *fa,
+                                          carve::mesh::MeshSet<3>::edge_t *eb);
+      void generateEdgeFaceIntersections(carve::mesh::MeshSet<3>::face_t *a,
+                                         const std::vector<carve::mesh::MeshSet<3>::face_t *> &b);
+
+      void generateIntersectionCandidates(carve::mesh::MeshSet<3> *a,
+                                          const face_rtree_t *a_node,
+                                          carve::mesh::MeshSet<3> *b,
+                                          const face_rtree_t *b_node,
+                                          face_pairs_t &face_pairs,
+                                          bool descend_a = true);
+      /** 
+       * \brief Compute all points of intersection between poly \a a and poly \a b
+       * 
+       * @param a Polyhedron a.
+       * @param b Polyhedron b.
+       */
+      void generateIntersections(meshset_t *a,
+                                 const face_rtree_t *a_node,
+                                 meshset_t *b,
+                                 const face_rtree_t *b_node,
+                                 detail::Data &data);
+
+      /** 
+       * \brief Generate tables of intersecting pairs of faces.
+       *
+       * @param[out] data Internal data-structure holding intersection info.
+       */
+      void intersectingFacePairs(detail::Data &data);
+
+      /** 
+       * \brief Divide edges in \a edges that are intersected by polyhedron \a poly
+       * 
+       * @param edges The edges to divide.
+       * @param[in] poly The polyhedron to divide against.
+       * @param[in,out] data Intersection information.
+       */
+      void divideEdges(
+        const std::vector<meshset_t::edge_t> &edges,
+        meshset_t *poly,
+        detail::Data &data);
+
+      void divideIntersectedEdges(detail::Data &data);
+
+      /** 
+       * \brief From the intersection points of pairs of intersecting faces, compute intersection edges.
+       * 
+       * @param[out] eclass Classification information about created edges.
+       * @param[in,out] data Intersection information.
+       */
+      void makeFaceEdges(
+        EdgeClassification &eclass,
+        detail::Data &data);
+
+      friend void classifyEasyFaces(
+        FaceLoopList &face_loops,
+        VertexClassification &vclass,
+        meshset_t *other_poly,
+        int other_poly_num,
+        CSG &csg,
+        CSG::Collector &collector);
+
+      size_t generateFaceLoops(
+        meshset_t *poly,
+        const detail::Data &data,
+        FaceLoopList &face_loops_out);
+
+
+
+      // intersect_group.cpp
+
+      /** 
+       * \brief Build a loop edge mapping from a list of face loops.
+       * 
+       * @param[in] loops A list of face loops.
+       * @param[in] edge_count A hint as to the number of edges in \a loops.
+       * @param[out] edge_map The calculated map of edges to loops.
+       */
+      void makeEdgeMap(
+        const FaceLoopList &loops,
+        size_t edge_count,
+        detail::LoopEdges &edge_map);
+
+      /** 
+       * \brief Divide a list of face loops into groups that are connected by at least one edge not present in \a no_cross.
+       * 
+       * @param[in] src The source mesh from which these loops derive.
+       * @param[in,out] face_loops The list of loops (will be emptied as a side effect)
+       * @param[in] loop_edges A loop edge map used for traversing connected loops.
+       * @param[in] no_cross A set of edges not to cross.
+       * @param[out] out_loops A list of grouped face loops.
+       */
+      void groupFaceLoops(
+        carve::mesh::MeshSet<3> *src,
+        FaceLoopList &face_loops,
+        const detail::LoopEdges &loop_edges,
+        const V2Set &no_cross,
+        FLGroupList &out_loops);
+
+      /** 
+       * \brief Find the set of edges shared between two edge maps.
+       * 
+       * @param[in] edge_map_a The first edge map.
+       * @param[in] edge_map_b The second edge map.
+       * @param[out] shared_edges The resulting set of common edges.
+       */
+      void findSharedEdges(
+        const detail::LoopEdges &edge_map_a,
+        const detail::LoopEdges &edge_map_b,
+        V2Set &shared_edges);
+
+
+      // intersect_classify_edge.cpp
+
+      /** 
+       * 
+       * 
+       * @param shared_edges 
+       * @param vclass 
+       * @param poly_a 
+       * @param a_loops_grouped 
+       * @param a_edge_map 
+       * @param poly_b 
+       * @param b_loops_grouped 
+       * @param b_edge_map 
+       * @param collector 
+       */
+      void classifyFaceGroupsEdge(
+        const V2Set &shared_edges,
+        VertexClassification &vclass,
+        meshset_t *poly_a,
+        const face_rtree_t *poly_a_rtree,
+        FLGroupList &a_loops_grouped,
+        const detail::LoopEdges &a_edge_map,
+        meshset_t *poly_b,
+        const face_rtree_t *poly_b_rtree,
+        FLGroupList &b_loops_grouped,
+        const detail::LoopEdges &b_edge_map,
+        CSG::Collector &collector);
+
+      // intersect_classify_group.cpp
+
+      /** 
+       * 
+       * 
+       * @param shared_edges 
+       * @param vclass 
+       * @param poly_a 
+       * @param a_loops_grouped 
+       * @param a_edge_map 
+       * @param poly_b 
+       * @param b_loops_grouped 
+       * @param b_edge_map 
+       * @param collector 
+       */
+      void classifyFaceGroups(
+        const V2Set &shared_edges,
+        VertexClassification &vclass,
+        meshset_t *poly_a, 
+        const face_rtree_t *poly_a_rtree,
+        FLGroupList &a_loops_grouped,
+        const detail::LoopEdges &a_edge_map,
+        meshset_t *poly_b,
+        const face_rtree_t *poly_b_rtree,
+        FLGroupList &b_loops_grouped,
+        const detail::LoopEdges &b_edge_map,
+        CSG::Collector &collector);
+
+      // intersect_half_classify_group.cpp
+
+      /** 
+       * 
+       * 
+       * @param shared_edges 
+       * @param vclass 
+       * @param poly_a 
+       * @param a_loops_grouped 
+       * @param a_edge_map 
+       * @param poly_b 
+       * @param b_loops_grouped 
+       * @param b_edge_map 
+       * @param FaceClass 
+       * @param b_out 
+       */
+      void halfClassifyFaceGroups(
+        const V2Set &shared_edges,
+        VertexClassification &vclass,
+        meshset_t *poly_a, 
+        const face_rtree_t *poly_a_rtree,
+        FLGroupList &a_loops_grouped,
+        const detail::LoopEdges &a_edge_map,
+        meshset_t *poly_b,
+        const face_rtree_t *poly_b_rtree,
+        FLGroupList &b_loops_grouped,
+        const detail::LoopEdges &b_edge_map,
+        std::list<std::pair<FaceClass, meshset_t  *> > &b_out);
+
+      // intersect.cpp
+
+      /** 
+       * \brief The main calculation method for CSG.
+       * 
+       * @param[in] a Polyhedron a
+       * @param[in] b Polyhedron b
+       * @param[out] vclass 
+       * @param[out] eclass 
+       * @param[out] a_face_loops 
+       * @param[out] b_face_loops 
+       * @param[out] a_edge_count 
+       * @param[out] b_edge_count 
+       */
+      void calc(
+        meshset_t  *a,
+        const face_rtree_t *a_rtree,
+        meshset_t  *b,
+        const face_rtree_t *b_rtree,
+        VertexClassification &vclass,
+        EdgeClassification &eclass,
+        FaceLoopList &a_face_loops,
+        FaceLoopList &b_face_loops,
+        size_t &a_edge_count,
+        size_t &b_edge_count);
+
+    public:
+      /**
+       * \enum OP
+       * \brief Enumeration of the supported CSG operations.
+       */
+      enum OP {
+        UNION,                  /**< in a or b. */
+        INTERSECTION,           /**< in a and b. */
+        A_MINUS_B,              /**< in a, but not b. */
+        B_MINUS_A,              /**< in b, but not a. */
+        SYMMETRIC_DIFFERENCE,   /**< in a or b, but not both. */
+        ALL                     /**< all split faces from a and b */
+      };
+
+      /**
+       * \enum CLASSIFY_TYPE
+       * \brief The type of classification algorithm to use.
+       */
+      enum CLASSIFY_TYPE {
+        CLASSIFY_NORMAL,        /**< Normal (group) classifier. */
+        CLASSIFY_EDGE           /**< Edge classifier. */
+      };
+
+      CSG::Hooks hooks;         /**< The manager for calculation hooks. */
+
+      CSG();
+      ~CSG();
+
+      /** 
+       * \brief Compute a CSG operation between two polyhedra, \a a and \a b.
+       * 
+       * @param a Polyhedron a
+       * @param b Polyhedron b
+       * @param collector The collector (determines the CSG operation performed)
+       * @param shared_edges A pointer to a set that will be populated with shared edges (if not NULL).
+       * @param classify_type The type of classifier to use.
+       * 
+       * @return 
+       */
+      meshset_t *compute(
+        meshset_t *a,
+        meshset_t *b,
+        CSG::Collector &collector,
+        V2Set *shared_edges = NULL,
+        CLASSIFY_TYPE classify_type = CLASSIFY_NORMAL);
+
+      /** 
+       * \brief Compute a CSG operation between two closed polyhedra, \a a and \a b.
+       * 
+       * @param a Polyhedron a
+       * @param b Polyhedron b
+       * @param op The CSG operation (A collector is created automatically).
+       * @param shared_edges A pointer to a set that will be populated with shared edges (if not NULL).
+       * @param classify_type The type of classifier to use.
+       * 
+       * @return 
+       */
+      meshset_t *compute(
+        meshset_t *a,
+        meshset_t *b,
+        OP op,
+        V2Set *shared_edges = NULL,
+        CLASSIFY_TYPE classify_type = CLASSIFY_NORMAL);
+
+      void slice(
+        meshset_t *a,
+        meshset_t *b,
+        std::list<meshset_t  *> &a_sliced,
+        std::list<meshset_t  *> &b_sliced,
+        V2Set *shared_edges = NULL);
+
+      bool sliceAndClassify(
+        meshset_t *closed,
+        meshset_t *open,
+        std::list<std::pair<FaceClass, meshset_t *> > &result,
+        V2Set *shared_edges = NULL);
+    };
+  }
+}
diff --git a/extern/carve/include/carve/csg_triangulator.hpp b/extern/carve/include/carve/csg_triangulator.hpp
new file mode 100644
index 00000000000..740585571bf
--- /dev/null
+++ b/extern/carve/include/carve/csg_triangulator.hpp
@@ -0,0 +1,434 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#include <carve/csg.hpp>
+#include <carve/tag.hpp>
+#include <carve/poly.hpp>
+#include <carve/triangulator.hpp>
+#include <deque>
+
+namespace carve {
+  namespace csg {
+
+    namespace detail {
+      template<bool with_improvement>
+      class CarveTriangulator : public csg::CSG::Hook {
+
+      public:
+        CarveTriangulator() {
+        }
+
+        virtual ~CarveTriangulator() {
+        }
+
+        virtual void processOutputFace(std::vector<carve::mesh::MeshSet<3>::face_t *> &faces,
+                                       const carve::mesh::MeshSet<3>::face_t *orig,
+                                       bool flipped) {
+          std::vector<carve::mesh::MeshSet<3>::face_t *> out_faces;
+
+          size_t n_tris = 0;
+          for (size_t f = 0; f < faces.size(); ++f) {
+            CARVE_ASSERT(faces[f]->nVertices() >= 3);
+            n_tris += faces[f]->nVertices() - 2;
+          }
+
+          out_faces.reserve(n_tris);
+
+          for (size_t f = 0; f < faces.size(); ++f) {
+            carve::mesh::MeshSet<3>::face_t *face = faces[f];
+
+            if (face->nVertices() == 3) {
+              out_faces.push_back(face);
+              continue;
+            }
+
+            std::vector<triangulate::tri_idx> result;
+
+            std::vector<carve::mesh::MeshSet<3>::vertex_t *> vloop;
+            face->getVertices(vloop);
+
+            triangulate::triangulate(
+                carve::mesh::MeshSet<3>::face_t::projection_mapping(face->project),
+                vloop,
+                result);
+
+            if (with_improvement) {
+              triangulate::improve(
+                  carve::mesh::MeshSet<3>::face_t::projection_mapping(face->project),
+                  vloop,
+                  carve::mesh::vertex_distance(),
+                  result);
+            }
+
+            std::vector<carve::mesh::MeshSet<3>::vertex_t *> fv;
+            fv.resize(3);
+            for (size_t i = 0; i < result.size(); ++i) {
+              fv[0] = vloop[result[i].a];
+              fv[1] = vloop[result[i].b];
+              fv[2] = vloop[result[i].c];
+              out_faces.push_back(face->create(fv.begin(), fv.end(), false));
+            }
+            delete face;
+          }
+          std::swap(faces, out_faces);
+        }
+      };
+    }
+
+    typedef detail::CarveTriangulator<false> CarveTriangulator;
+    typedef detail::CarveTriangulator<true> CarveTriangulatorWithImprovement;
+
+    class CarveTriangulationImprover : public csg::CSG::Hook {
+    public:
+      CarveTriangulationImprover() {
+      }
+
+      virtual ~CarveTriangulationImprover() {
+      }
+
+      virtual void processOutputFace(std::vector<carve::mesh::MeshSet<3>::face_t *> &faces,
+                                     const carve::mesh::MeshSet<3>::face_t *orig,
+                                     bool flipped) {
+        if (faces.size() == 1) return;
+
+        // doing improvement as a separate hook is much messier than
+        // just incorporating it into the triangulation hook.
+
+        typedef std::map<carve::mesh::MeshSet<3>::vertex_t *, size_t> vert_map_t;
+        std::vector<carve::mesh::MeshSet<3>::face_t *> out_faces;
+        vert_map_t vert_map;
+
+        out_faces.reserve(faces.size());
+
+
+        carve::mesh::MeshSet<3>::face_t::projection_mapping projector(faces[0]->project);
+
+        std::vector<triangulate::tri_idx> result;
+
+        for (size_t f = 0; f < faces.size(); ++f) {
+          carve::mesh::MeshSet<3>::face_t *face = faces[f];
+          if (face->nVertices() != 3) {
+            out_faces.push_back(face);
+          } else {
+            triangulate::tri_idx tri;
+            for (carve::mesh::MeshSet<3>::face_t::edge_iter_t i = face->begin(); i != face->end(); ++i) {
+              size_t v = 0;
+              vert_map_t::iterator j = vert_map.find(i->vert);
+              if (j == vert_map.end()) {
+                v = vert_map.size();
+                vert_map[i->vert] = v;
+              } else {
+                v = (*j).second;
+              }
+              tri.v[i.idx()] = v;
+            }
+            result.push_back(tri);
+            delete face;
+          }
+        }
+
+        std::vector<carve::mesh::MeshSet<3>::vertex_t *> verts;
+        verts.resize(vert_map.size());
+        for (vert_map_t::iterator i = vert_map.begin(); i != vert_map.end(); ++i) {
+          verts[(*i).second] = (*i).first;
+        }
+ 
+        triangulate::improve(projector, verts, carve::mesh::vertex_distance(), result);
+
+        std::vector<carve::mesh::MeshSet<3>::vertex_t *> fv;
+        fv.resize(3);
+        for (size_t i = 0; i < result.size(); ++i) {
+          fv[0] = verts[result[i].a];
+          fv[1] = verts[result[i].b];
+          fv[2] = verts[result[i].c];
+          out_faces.push_back(orig->create(fv.begin(), fv.end(), false));
+        }
+
+        std::swap(faces, out_faces);
+      }
+    };
+
+    class CarveTriangulationQuadMerger : public csg::CSG::Hook {
+      // this code is incomplete.
+      typedef std::map<V2, F2> edge_map_t;
+
+    public:
+      CarveTriangulationQuadMerger() {
+      }
+
+      virtual ~CarveTriangulationQuadMerger() {
+      }
+
+      double scoreQuad(edge_map_t::iterator i, edge_map_t &edge_map) {
+        if (!(*i).second.first || !(*i).second.second) return -1;
+        return 0;
+      }
+
+      carve::mesh::MeshSet<3>::face_t *mergeQuad(edge_map_t::iterator i, edge_map_t &edge_map) {
+        return NULL;
+      }
+
+      void recordEdge(carve::mesh::MeshSet<3>::vertex_t *v1,
+                      carve::mesh::MeshSet<3>::vertex_t *v2,
+                      carve::mesh::MeshSet<3>::face_t *f,
+                      edge_map_t &edge_map) {
+        if (v1 < v2) {
+          edge_map[V2(v1, v2)].first = f;
+        } else {
+          edge_map[V2(v2, v1)].second = f;
+        }
+      }
+
+      virtual void processOutputFace(std::vector<carve::mesh::MeshSet<3>::face_t *> &faces,
+                                     const carve::mesh::MeshSet<3>::face_t *orig,
+                                     bool flipped) {
+        if (faces.size() == 1) return;
+
+        std::vector<carve::mesh::MeshSet<3>::face_t *> out_faces;
+        edge_map_t edge_map;
+
+        out_faces.reserve(faces.size());
+
+        poly::p2_adapt_project<3> projector(faces[0]->project);
+
+        for (size_t f = 0; f < faces.size(); ++f) {
+          carve::mesh::MeshSet<3>::face_t *face = faces[f];
+          if (face->nVertices() != 3) {
+            out_faces.push_back(face);
+          } else {
+            carve::mesh::MeshSet<3>::face_t::vertex_t *v1, *v2, *v3;
+            v1 = face->edge->vert;
+            v2 = face->edge->next->vert;
+            v3 = face->edge->next->next->vert;
+            recordEdge(v1, v2, face, edge_map);
+            recordEdge(v2, v3, face, edge_map);
+            recordEdge(v3, v1, face, edge_map);
+          }
+        }
+
+        for (edge_map_t::iterator i = edge_map.begin(); i != edge_map.end();) {
+          if ((*i).second.first && (*i).second.second) {
+            ++i;
+          } else {
+            edge_map.erase(i++);
+          }
+        }
+
+        while (edge_map.size()) {
+          edge_map_t::iterator i = edge_map.begin();
+          edge_map_t::iterator best = i;
+          double best_score = scoreQuad(i, edge_map);
+          for (++i; i != edge_map.end(); ++i) {
+            double score = scoreQuad(i, edge_map);
+            if (score > best_score) best = i;
+          }
+          if (best_score < 0) break;
+          out_faces.push_back(mergeQuad(best, edge_map));
+        }
+
+        if (edge_map.size()) {
+          tagable::tag_begin();
+          for (edge_map_t::iterator i = edge_map.begin(); i != edge_map.end(); ++i) {
+            carve::mesh::MeshSet<3>::face_t *a = const_cast<carve::mesh::MeshSet<3>::face_t *>((*i).second.first);
+            carve::mesh::MeshSet<3>::face_t *b = const_cast<carve::mesh::MeshSet<3>::face_t *>((*i).second.first);
+            if (a && a->tag_once()) out_faces.push_back(a);
+            if (b && b->tag_once()) out_faces.push_back(b);
+          }
+        }
+
+        std::swap(faces, out_faces);
+      }
+    };
+
+    class CarveHoleResolver : public csg::CSG::Hook {
+
+    public:
+      CarveHoleResolver() {
+      }
+
+      virtual ~CarveHoleResolver() {
+      }
+
+      bool findRepeatedEdges(const std::vector<carve::mesh::MeshSet<3>::vertex_t *> &vertices,
+                             std::list<std::pair<size_t, size_t> > &edge_pos) {
+        std::map<V2, size_t> edges;
+        for (size_t i = 0; i < vertices.size() - 1; ++i) {
+          edges[std::make_pair(vertices[i], vertices[i+1])] = i;
+        }
+        edges[std::make_pair(vertices[vertices.size()-1], vertices[0])] = vertices.size() - 1;
+
+        for (std::map<V2, size_t>::iterator i = edges.begin(); i != edges.end(); ++i) {
+          V2 rev = V2((*i).first.second, (*i).first.first);
+          std::map<V2, size_t>::iterator j = edges.find(rev);
+          if (j != edges.end()) {
+            edge_pos.push_back(std::make_pair((*i).second, (*j).second));
+          }
+        }
+        return edge_pos.size() > 0;
+      }
+
+      void flood(size_t t1,
+                 size_t t2,
+                 size_t old_grp,
+                 size_t new_grp_1,
+                 size_t new_grp_2,
+                 std::vector<size_t> &grp,
+                 const std::vector<triangulate::tri_idx> &tris,
+                 const std::map<std::pair<size_t, size_t>, size_t> &tri_edge) {
+        grp[t1] = new_grp_1;
+        grp[t2] = new_grp_2;
+
+        std::deque<size_t> to_visit;
+        to_visit.push_back(t1);
+        to_visit.push_back(t2);
+        std::vector<std::pair<size_t, size_t> > rev;
+        rev.resize(3);
+        while (to_visit.size()) {
+          size_t curr = to_visit.front();
+          to_visit.pop_front();
+          triangulate::tri_idx ct = tris[curr];
+          rev[0] = std::make_pair(ct.b, ct.a);
+          rev[1] = std::make_pair(ct.c, ct.b);
+          rev[2] = std::make_pair(ct.a, ct.c);
+
+          for (size_t i = 0; i < 3; ++i) {
+            std::map<std::pair<size_t, size_t>, size_t>::const_iterator adj = tri_edge.find(rev[i]);
+            if (adj == tri_edge.end()) continue;
+            size_t next = (*adj).second;
+            if (grp[next] != old_grp) continue;
+            grp[next] = grp[curr];
+            to_visit.push_back(next);
+          }
+        }
+      }
+
+      void findPerimeter(const std::vector<triangulate::tri_idx> &tris,
+                         const std::vector<carve::mesh::MeshSet<3>::vertex_t *> &verts,
+                         std::vector<carve::mesh::MeshSet<3>::vertex_t *> &out) {
+        std::map<std::pair<size_t, size_t>, size_t> edges;
+        for (size_t i = 0; i < tris.size(); ++i) {
+          edges[std::make_pair(tris[i].a, tris[i].b)] = i;
+          edges[std::make_pair(tris[i].b, tris[i].c)] = i;
+          edges[std::make_pair(tris[i].c, tris[i].a)] = i;
+        }
+        std::map<size_t, size_t> unpaired;
+        for (std::map<std::pair<size_t, size_t>, size_t>::iterator i = edges.begin(); i != edges.end(); ++i) {
+          if (edges.find(std::make_pair((*i).first.second, (*i).first.first)) == edges.end()) {
+            CARVE_ASSERT(unpaired.find((*i).first.first) == unpaired.end());
+            unpaired[(*i).first.first] = (*i).first.second;
+          }
+        }
+        out.clear();
+        out.reserve(unpaired.size());
+        size_t start = (*unpaired.begin()).first;
+        size_t vert = start;
+        do {
+          out.push_back(verts[vert]);
+          CARVE_ASSERT(unpaired.find(vert) != unpaired.end());
+          vert = unpaired[vert];
+        } while (vert != start);
+      }
+
+      virtual void processOutputFace(std::vector<carve::mesh::MeshSet<3>::face_t *> &faces,
+                                     const carve::mesh::MeshSet<3>::face_t *orig,
+                                     bool flipped) {
+        std::vector<carve::mesh::MeshSet<3>::face_t *> out_faces;
+
+        for (size_t f = 0; f < faces.size(); ++f) {
+          carve::mesh::MeshSet<3>::face_t *face = faces[f];
+
+          if (face->nVertices() == 3) {
+            out_faces.push_back(face);
+            continue;
+          }
+
+          std::vector<carve::mesh::MeshSet<3>::vertex_t *> vloop;
+          face->getVertices(vloop);
+
+          std::list<std::pair<size_t, size_t> > rep_edges;
+          if (!findRepeatedEdges(vloop, rep_edges)) {
+            out_faces.push_back(face);
+            continue;
+          }
+
+          std::vector<triangulate::tri_idx> result;
+          triangulate::triangulate(
+              carve::mesh::MeshSet<3>::face_t::projection_mapping(face->project),
+              vloop,
+              result);
+
+          std::map<std::pair<size_t, size_t>, size_t> tri_edge;
+          for (size_t i = 0; i < result.size(); ++i) {
+            tri_edge[std::make_pair(result[i].a, result[i].b)] = i;
+            tri_edge[std::make_pair(result[i].b, result[i].c)] = i;
+            tri_edge[std::make_pair(result[i].c, result[i].a)] = i;
+          }
+
+          std::vector<size_t> grp;
+          grp.resize(result.size(), 0);
+
+          size_t grp_max = 0;
+
+          while (rep_edges.size()) {
+            std::pair<size_t, size_t> e1, e2;
+
+            e1.first = rep_edges.front().first;
+            e1.second = (e1.first + 1) % vloop.size();
+
+            e2.first = rep_edges.front().second;
+            e2.second = (e2.first + 1) % vloop.size();
+
+            rep_edges.pop_front();
+
+            CARVE_ASSERT(tri_edge.find(e1) != tri_edge.end());
+            size_t t1 = tri_edge[e1];
+            CARVE_ASSERT(tri_edge.find(e2) != tri_edge.end());
+            size_t t2 = tri_edge[e2];
+
+            if (grp[t1] != grp[t2]) {
+              continue;
+            }
+
+            size_t t1g = ++grp_max;
+            size_t t2g = ++grp_max;
+
+            flood(t1, t2, grp[t1], t1g, t2g, grp, result, tri_edge);
+          }
+
+          std::set<size_t> groups;
+          std::copy(grp.begin(), grp.end(), std::inserter(groups, groups.begin()));
+
+          // now construct perimeters for each group.
+          std::vector<triangulate::tri_idx> grp_tris;
+          grp_tris.reserve(result.size());
+          for (std::set<size_t>::iterator i = groups.begin(); i != groups.end(); ++i) {
+            size_t grp_id = *i;
+            grp_tris.clear();
+            for (size_t j = 0; j < grp.size(); ++j) {
+              if (grp[j] == grp_id) {
+                grp_tris.push_back(result[j]);
+              }
+            }
+            std::vector<carve::mesh::MeshSet<3>::vertex_t *> grp_perim;
+            findPerimeter(grp_tris, vloop, grp_perim);
+            out_faces.push_back(face->create(grp_perim.begin(), grp_perim.end(), false));
+          }
+        }
+        std::swap(faces, out_faces);
+      }
+    };
+  }
+}
diff --git a/extern/carve/include/carve/debug_hooks.hpp b/extern/carve/include/carve/debug_hooks.hpp
new file mode 100644
index 00000000000..9ef7fc83573
--- /dev/null
+++ b/extern/carve/include/carve/debug_hooks.hpp
@@ -0,0 +1,97 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/vector.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/csg.hpp>
+
+#include <iomanip>
+
+template<typename MAP>
+void map_histogram(std::ostream &out, const MAP &map) {
+  std::vector<int> hist;
+  for (typename MAP::const_iterator i = map.begin(); i != map.end(); ++i) {
+    size_t n = (*i).second.size();
+    if (hist.size() <= n) {
+      hist.resize(n + 1);
+    }
+    hist[n]++;
+  }
+  int total = map.size();
+  std::string bar(50, '*');
+  for (size_t i = 0; i < hist.size(); i++) {
+    if (hist[i] > 0) {
+      out << std::setw(5) << i << " : " << std::setw(5) << hist[i] << " " << bar.substr(50 - hist[i] * 50 / total) << std::endl;
+    }
+  }
+}
+
+namespace carve {
+  namespace csg {
+    class IntersectDebugHooks {
+    public:
+      virtual void drawIntersections(const VertexIntersections & /* vint */) {
+      }
+
+      virtual void drawPoint(const carve::mesh::MeshSet<3>::vertex_t * /* v */,
+                             float /* r */,
+                             float /* g */,
+                             float /* b */,
+                             float /* a */,
+                             float /* rad */) {
+      }
+      virtual void drawEdge(const carve::mesh::MeshSet<3>::vertex_t * /* v1 */,
+                            const carve::mesh::MeshSet<3>::vertex_t * /* v2 */,
+                            float /* rA */, float /* gA */, float /* bA */, float /* aA */,
+                            float /* rB */, float /* gB */, float /* bB */, float /* aB */,
+                            float /* thickness */ = 1.0) {
+      }
+
+      virtual void drawFaceLoopWireframe(const std::vector<carve::mesh::MeshSet<3>::vertex_t *> & /* face_loop */,
+                                         const carve::mesh::MeshSet<3>::vertex_t & /* normal */,
+                                         float /* r */, float /* g */, float /* b */, float /* a */,
+                                         bool /* inset */ = true) {
+      }
+
+      virtual void drawFaceLoop(const std::vector<carve::mesh::MeshSet<3>::vertex_t *> & /* face_loop */,
+                                const carve::mesh::MeshSet<3>::vertex_t & /* normal */,
+                                float /* r */, float /* g */, float /* b */, float /* a */,
+                                bool /* offset */ = true,
+                                bool /* lit */ = true) {
+      }
+
+      virtual void drawFaceLoop2(const std::vector<carve::mesh::MeshSet<3>::vertex_t *> & /* face_loop */,
+                                 const carve::mesh::MeshSet<3>::vertex_t & /* normal */,
+                                 float /* rF */, float /* gF */, float /* bF */, float /* aF */,
+                                 float /* rB */, float /* gB */, float /* bB */, float /* aB */,
+                                 bool /* offset */ = true,
+                                 bool /* lit */ = true) {
+      }
+
+      virtual ~IntersectDebugHooks() {
+      }
+    };
+
+    IntersectDebugHooks *intersect_installDebugHooks(IntersectDebugHooks *hooks);
+    bool intersect_debugEnabled();
+
+  }
+}
diff --git a/extern/carve/include/carve/djset.hpp b/extern/carve/include/carve/djset.hpp
new file mode 100644
index 00000000000..542858d59f4
--- /dev/null
+++ b/extern/carve/include/carve/djset.hpp
@@ -0,0 +1,134 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <vector>
+
+
+
+namespace carve {
+namespace djset {
+
+
+
+  class djset {
+
+  protected:
+    struct elem {
+      size_t parent, rank;
+      elem(size_t p, size_t r) : parent(p), rank(r) {}
+      elem() {}
+    };
+
+    std::vector<elem> set;
+    size_t n_sets;
+
+  public:
+    djset() : set(), n_sets(0) {
+    }
+
+    djset(size_t N) {
+      n_sets = N;
+      set.reserve(N);
+      for (size_t i = 0; i < N; ++i) {
+        set.push_back(elem(i,0));
+      }
+    }
+
+    void init(size_t N) {
+      if (N == set.size()) {
+        for (size_t i = 0; i < N; ++i) {
+          set[i] = elem(i,0);
+        }
+        n_sets = N;
+      } else {
+        djset temp(N);
+        std::swap(set, temp.set);
+        std::swap(n_sets, temp.n_sets);
+      }
+    }
+
+    size_t count() const {
+      return n_sets;
+    }
+
+    size_t find_set_head(size_t a) {
+      if (a == set[a].parent) return a;
+    
+      size_t a_head = a;
+      while (set[a_head].parent != a_head) a_head = set[a_head].parent;
+      set[a].parent = a_head;
+      return a_head;
+    }
+
+    bool same_set(size_t a, size_t b) {
+      return find_set_head(a) == find_set_head(b);
+    }
+
+    void merge_sets(size_t a, size_t b) {
+      a = find_set_head(a);
+      b = find_set_head(b);
+      if (a != b) {
+        n_sets--;
+        if (set[a].rank < set[b].rank) {
+          set[a].parent = b;
+        } else if (set[b].rank < set[a].rank) {
+          set[b].parent = a;
+        } else {
+          set[a].rank++;
+          set[b].parent = a;
+        }
+      }
+    }
+
+    void get_index_to_set(std::vector<size_t> &index_set, std::vector<size_t> &set_size) {
+      index_set.clear();
+      index_set.resize(set.size(), n_sets);
+      set_size.clear();
+      set_size.resize(n_sets, 0);
+
+      size_t c = 0;
+      for (size_t i = 0; i < set.size(); ++i) {
+        size_t s = find_set_head(i);
+        if (index_set[s] == n_sets) index_set[s] = c++;
+        index_set[i] = index_set[s];
+        set_size[index_set[s]]++;
+      }
+    }
+
+    template<typename in_iter_t, typename out_collection_t>
+    void collate(in_iter_t in, out_collection_t &out) {
+      std::vector<size_t> set_id(set.size(), n_sets);
+      out.clear();
+      out.resize(n_sets);
+      size_t c = 0;
+      for (size_t i = 0; i < set.size(); ++i) {
+        size_t s = find_set_head(i);
+        if (set_id[s] == n_sets) set_id[s] = c++;
+        s = set_id[s];
+        std::insert_iterator<typename out_collection_t::value_type> j(out[s], out[s].end());
+        *j = *in++;
+      }
+    }
+  };
+
+
+
+}
+}
diff --git a/extern/carve/include/carve/edge_decl.hpp b/extern/carve/include/carve/edge_decl.hpp
new file mode 100644
index 00000000000..cafef5de7b1
--- /dev/null
+++ b/extern/carve/include/carve/edge_decl.hpp
@@ -0,0 +1,68 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/vector.hpp>
+#include <carve/tag.hpp>
+
+#include <vector>
+#include <list>
+
+namespace carve {
+  namespace poly {
+
+
+
+    struct Object;
+
+
+
+    template<unsigned ndim>
+    class Edge : public tagable {
+    public:
+      typedef Vertex<ndim> vertex_t;
+      typedef typename Vertex<ndim>::vector_t vector_t;
+      typedef Object obj_t;
+
+      const vertex_t *v1, *v2;
+      const obj_t *owner;
+
+      Edge(const vertex_t *_v1, const vertex_t *_v2, const obj_t *_owner) :
+        tagable(), v1(_v1), v2(_v2), owner(_owner) {
+      }
+
+      ~Edge() {
+      }
+    };
+
+
+
+    struct hash_edge_ptr {
+      template<unsigned ndim>
+      size_t operator()(const Edge<ndim> * const &e) const {
+        return (size_t)e;
+      }
+    };
+
+
+
+  }
+}
+
diff --git a/extern/carve/include/carve/edge_impl.hpp b/extern/carve/include/carve/edge_impl.hpp
new file mode 100644
index 00000000000..504972c7de0
--- /dev/null
+++ b/extern/carve/include/carve/edge_impl.hpp
@@ -0,0 +1,23 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+namespace carve {
+  namespace poly {
+  }
+}
diff --git a/extern/carve/include/carve/exact.hpp b/extern/carve/include/carve/exact.hpp
new file mode 100644
index 00000000000..afb491211fd
--- /dev/null
+++ b/extern/carve/include/carve/exact.hpp
@@ -0,0 +1,702 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <vector>
+#include <numeric>
+#include <algorithm>
+
+
+namespace carve {
+  namespace exact {
+
+    class exact_t : public std::vector<double> {
+      typedef std::vector<double> super;
+
+    public:
+      exact_t() : super() {
+      }
+
+      exact_t(double v, size_t sz = 1) : super(sz, v) {
+      }
+
+      template<typename iter_t>
+      exact_t(iter_t a, iter_t b) : super(a, b) {
+      }
+
+      exact_t(double a, double b) : super() {
+        reserve(2);
+        push_back(a);
+        push_back(b);
+      }
+
+      exact_t(double a, double b, double c) : super() {
+        reserve(3);
+        push_back(a);
+        push_back(b);
+        push_back(c);
+      }
+
+      exact_t(double a, double b, double c, double d) : super() {
+        reserve(4);
+        push_back(a);
+        push_back(b);
+        push_back(c);
+        push_back(d);
+      }
+
+      exact_t(double a, double b, double c, double d, double e) : super() {
+        reserve(5);
+        push_back(a);
+        push_back(b);
+        push_back(c);
+        push_back(d);
+        push_back(e);
+      }
+
+      exact_t(double a, double b, double c, double d, double e, double f) : super() {
+        reserve(6);
+        push_back(a);
+        push_back(b);
+        push_back(c);
+        push_back(d);
+        push_back(e);
+        push_back(f);
+      }
+
+      exact_t(double a, double b, double c, double d, double e, double f, double g) : super() {
+        reserve(7);
+        push_back(a);
+        push_back(b);
+        push_back(c);
+        push_back(d);
+        push_back(e);
+        push_back(f);
+        push_back(g);
+      }
+
+      exact_t(double a, double b, double c, double d, double e, double f, double g, double h) : super() {
+        reserve(8);
+        push_back(a);
+        push_back(b);
+        push_back(c);
+        push_back(d);
+        push_back(e);
+        push_back(f);
+        push_back(g);
+        push_back(h);
+      }
+
+      void compress();
+
+      exact_t compressed() const {
+        exact_t result(*this);
+        result.compress();
+        return result;
+      }
+
+      operator double() const {
+        return std::accumulate(begin(), end(), 0.0);
+      }
+
+      void removeZeroes() {
+        erase(std::remove(begin(), end(), 0.0), end());
+      }
+    };
+
+    inline std::ostream &operator<<(std::ostream &out, const exact_t &p) {
+      out << '{';
+      out << p[0];
+      for (size_t i = 1; i < p.size(); ++i) out << ';' << p[i];
+      out << '}';
+      return out;
+    }
+
+
+
+    namespace detail {
+      const struct constants_t {
+        double splitter;     /* = 2^ceiling(p / 2) + 1.  Used to split floats in half. */
+        double epsilon;                /* = 2^(-p).  Used to estimate roundoff errors. */
+        /* A set of coefficients used to calculate maximum roundoff errors.          */
+        double resulterrbound;
+        double ccwerrboundA, ccwerrboundB, ccwerrboundC;
+        double o3derrboundA, o3derrboundB, o3derrboundC;
+        double iccerrboundA, iccerrboundB, iccerrboundC;
+        double isperrboundA, isperrboundB, isperrboundC;
+
+        constants_t() {
+          double half;
+          double check, lastcheck;
+          int every_other;
+  
+          every_other = 1;
+          half = 0.5;
+          epsilon = 1.0;
+          splitter = 1.0;
+          check = 1.0;
+          /* Repeatedly divide `epsilon' by two until it is too small to add to    */
+          /*   one without causing roundoff.  (Also check if the sum is equal to   */
+          /*   the previous sum, for machines that round up instead of using exact */
+          /*   rounding.  Not that this library will work on such machines anyway. */
+          do {
+            lastcheck = check;
+            epsilon *= half;
+            if (every_other) {
+              splitter *= 2.0;
+            }
+            every_other = !every_other;
+            check = 1.0 + epsilon;
+          } while ((check != 1.0) && (check != lastcheck));
+          splitter += 1.0;
+  
+          /* Error bounds for orientation and incircle tests. */
+          resulterrbound = (3.0 + 8.0 * epsilon) * epsilon;
+          ccwerrboundA = (3.0 + 16.0 * epsilon) * epsilon;
+          ccwerrboundB = (2.0 + 12.0 * epsilon) * epsilon;
+          ccwerrboundC = (9.0 + 64.0 * epsilon) * epsilon * epsilon;
+          o3derrboundA = (7.0 + 56.0 * epsilon) * epsilon;
+          o3derrboundB = (3.0 + 28.0 * epsilon) * epsilon;
+          o3derrboundC = (26.0 + 288.0 * epsilon) * epsilon * epsilon;
+          iccerrboundA = (10.0 + 96.0 * epsilon) * epsilon;
+          iccerrboundB = (4.0 + 48.0 * epsilon) * epsilon;
+          iccerrboundC = (44.0 + 576.0 * epsilon) * epsilon * epsilon;
+          isperrboundA = (16.0 + 224.0 * epsilon) * epsilon;
+          isperrboundB = (5.0 + 72.0 * epsilon) * epsilon;
+          isperrboundC = (71.0 + 1408.0 * epsilon) * epsilon * epsilon;
+        }
+      } constants;
+
+      template<unsigned U, unsigned V>
+      struct op {
+        enum {
+          Vlo = V / 2,
+          Vhi = V - Vlo
+        };
+
+        static inline void add(const double *a, const double *b, double *r) {
+          double t[U + Vlo];
+          op<U, Vlo>::add(a, b, t);
+          for (size_t i = 0; i < Vlo; ++i) r[i] = t[i];
+          op<U, Vhi>::add(t + Vlo, b + Vlo, r + Vlo);
+        }
+
+        static inline void sub(const double *a, const double *b, double *r) {
+          double t[U + Vlo];
+          op<U, Vlo>::sub(a, b, t);
+          for (size_t i = 0; i < Vlo; ++i) r[i] = t[i];
+          op<U, Vhi>::sub(t + Vlo, b + Vlo, r + Vlo);
+        }
+      };
+
+      template<unsigned U>
+      struct op<U, 1> {
+        enum {
+          Ulo = U / 2,
+          Uhi = U - Ulo
+        };
+        static void add(const double *a, const double *b, double *r) {
+          double t[Ulo + 1];
+          op<Ulo, 1>::add(a, b, t);
+          for (size_t i = 0; i < Ulo; ++i) r[i] = t[i];
+          op<Uhi, 1>::add(a + Ulo, t + Ulo, r + Ulo);
+        }
+
+        static void sub(const double *a, const double *b, double *r) {
+          double t[Ulo + 1];
+          op<Ulo, 1>::sub(a, b, t);
+          for (size_t i = 0; i < Ulo; ++i) r[i] = t[i];
+          op<Uhi, 1>::add(a + Ulo, t + Ulo, r + Ulo);
+        }
+      };
+
+      template<>
+      struct op<1, 1> {
+        static void add_fast(const double *a, const double *b, double *r) {
+          assert(fabs(a[0]) >= fabs(b[0]));
+          volatile double sum = a[0] + b[0];
+          volatile double bvirt = sum - a[0];
+          r[0] = b[0] - bvirt;
+          r[1] = sum;
+        }
+
+        static void sub_fast(const double *a, const double *b, double *r) {
+          assert(fabs(a[0]) >= fabs(b[0]));
+          volatile double diff = a[0] - b[0];
+          volatile double bvirt = a[0] - diff;
+          r[0] = bvirt - b[0];
+          r[1] = diff;
+        }
+
+        static void add(const double *a, const double *b, double *r) {
+          volatile double sum = a[0] + b[0];
+          volatile double bvirt = sum - a[0];
+          double avirt = sum - bvirt;
+          double bround = b[0] - bvirt;
+          double around = a[0] - avirt;
+          r[0] = around + bround;
+          r[1] = sum;
+        }
+
+        static void sub(const double *a, const double *b, double *r) {
+          volatile double diff = a[0] - b[0];
+          volatile double bvirt = a[0] - diff;
+          double avirt = diff + bvirt;
+          double bround = bvirt - b[0];
+          double around = a[0] - avirt;
+          r[0] = around + bround;
+          r[1] = diff;
+        }
+      };
+
+
+      template<unsigned U, unsigned V>
+      static exact_t add(const double *a, const double *b) {
+        exact_t result;
+        result.resize(U + V);
+        op<U,V>::add(a, b, &result[0]);
+        return result;
+      }
+
+
+      template<unsigned U, unsigned V>
+      static exact_t sub(const double *a, const double *b) {
+        exact_t result;
+        result.resize(U + V);
+        op<U,V>::sub(a, b, &result[0]);
+        return result;
+      }
+
+
+      template<unsigned U, unsigned V>
+      static exact_t add(const exact_t &a, const exact_t &b) {
+        assert(a.size() == U);
+        assert(b.size() == V);
+        exact_t result;
+        result.resize(U + V);
+        std::fill(result.begin(), result.end(), std::numeric_limits<double>::quiet_NaN());
+        op<U,V>::add(&a[0], &b[0], &result[0]);
+        return result;
+      }
+
+
+      template<unsigned U, unsigned V>
+      static exact_t add(const exact_t &a, const double *b) {
+        assert(a.size() == U);
+        exact_t result;
+        result.resize(U + V);
+        std::fill(result.begin(), result.end(), std::numeric_limits<double>::quiet_NaN());
+        op<U,V>::add(&a[0], b, &result[0]);
+        return result;
+      }
+
+
+      template<unsigned U, unsigned V>
+      static exact_t sub(const exact_t &a, const exact_t &b) {
+        assert(a.size() == U);
+        assert(b.size() == V);
+        exact_t result;
+        result.resize(U + V);
+        std::fill(result.begin(), result.end(), std::numeric_limits<double>::quiet_NaN());
+        op<U,V>::sub(&a[0], &b[0], &result[0]);
+        return result;
+      }
+
+
+      template<unsigned U, unsigned V>
+      static exact_t sub(const exact_t &a, const double *b) {
+        assert(a.size() == U);
+        exact_t result;
+        result.resize(U + V);
+        std::fill(result.begin(), result.end(), std::numeric_limits<double>::quiet_NaN());
+        op<U,V>::sub(&a[0], &b[0], &result[0]);
+        return result;
+      }
+
+
+      static inline void split(const double a, double *r) {
+        volatile double c = constants.splitter * a;
+        volatile double abig = c - a;
+        r[1] = c - abig;
+        r[0] = a - r[1];
+      }
+
+      static inline void prod_1_1(const double *a, const double *b, double *r) {
+        r[1] = a[0] * b[0];
+        double a_sp[2]; split(a[0], a_sp);
+        double b_sp[2]; split(b[0], b_sp);
+        double err1 = r[1] - a_sp[1] * b_sp[1];
+        double err2 = err1 - a_sp[0] * b_sp[1];
+        double err3 = err2 - a_sp[1] * b_sp[0];
+        r[0] = a_sp[0] * b_sp[0] - err3;
+      }
+
+      static inline void prod_1_1s(const double *a, const double *b, const double *b_sp, double *r) {
+        r[1] = a[0] * b[0];
+        double a_sp[2]; split(a[0], a_sp);
+        double err1 = r[1] - a_sp[1] * b_sp[1];
+        double err2 = err1 - a_sp[0] * b_sp[1];
+        double err3 = err2 - a_sp[1] * b_sp[0];
+        r[0] = a_sp[0] * b_sp[0] - err3;
+      }
+
+      static inline void prod_1s_1s(const double *a, const double *a_sp, const double *b, const double *b_sp, double *r) {
+        r[1] = a[0] * b[0];
+        double err1 = r[1] - a_sp[1] * b_sp[1];
+        double err2 = err1 - a_sp[0] * b_sp[1];
+        double err3 = err2 - a_sp[1] * b_sp[0];
+        r[0] = a_sp[0] * b_sp[0] - err3;
+      }
+
+      static inline void prod_2_1(const double *a, const double *b, double *r) {
+        double b_sp[2]; split(b[0], b_sp);
+        double t1[2]; prod_1_1s(a+0, b, b_sp, t1);
+        r[0] = t1[0];
+        double t2[2]; prod_1_1s(a+1, b, b_sp, t2);
+        double t3[2]; op<1,1>::add(t1+1, t2, t3);
+        r[1] = t3[0];
+        double t4[2]; op<1,1>::add_fast(t2+1, t3+1, r + 2);
+      }
+
+      static inline void prod_1_2(const double *a, const double *b, double *r) {
+        prod_2_1(b, a, r);
+      }
+
+      static inline void prod_4_1(const double *a, const double *b, double *r) {
+        double b_sp[2]; split(b[0], b_sp);
+        double t1[2]; prod_1_1s(a+0, b, b_sp, t1);
+        r[0] = t1[0];
+        double t2[2]; prod_1_1s(a+1, b, b_sp, t2);
+        double t3[2]; op<1,1>::add(t1+1, t2, t3);
+        r[1] = t3[0];
+        double t4[2]; op<1,1>::add_fast(t2+1, t3+1, t4);
+        r[2] = t4[0];
+        double t5[2]; prod_1_1s(a+2, b, b_sp, t5);
+        double t6[2]; op<1,1>::add(t4+1, t5, t6);
+        r[3] = t6[0];
+        double t7[2]; op<1,1>::add_fast(t5+1, t6+1, t7);
+        r[4] = t7[0];
+        double t8[2]; prod_1_1s(a+3, b, b_sp, t8);
+        double t9[2]; op<1,1>::add(t7+1, t8, t9);
+        r[5] = t9[0];
+        op<1,1>::add_fast(t8+1, t9+1, r + 6);
+      }
+
+      static inline void prod_1_4(const double *a, const double *b, double *r) {
+        prod_4_1(b, a, r);
+      }
+
+      static inline void prod_2_2(const double *a, const double *b, double *r) {
+        double a1_sp[2]; split(a[1], a1_sp);
+        double a0_sp[2]; split(a[0], a0_sp);
+        double b1_sp[2]; split(b[1], b1_sp);
+        double b0_sp[2]; split(b[0], b0_sp);
+
+        double t1[2]; prod_1s_1s(a+0, a0_sp, b+0, b0_sp, t1);
+        r[0] = t1[0];
+        double t2[2]; prod_1s_1s(a+1, a1_sp, b+0, b0_sp, t2);
+
+        double t3[2]; op<1,1>::add(t1+1, t2, t3);
+        double t4[2]; op<1,1>::add_fast(t2+1, t3+1, t4);
+
+        double t5[2]; prod_1s_1s(a+0, a0_sp, b+1, b1_sp, t5);
+
+        double t6[2]; op<1,1>::add(t3, t5, t6);
+        r[1] = t6[0];
+        double t7[2]; op<1,1>::add(t4, t6+1, t7);
+        double t8[2]; op<1,1>::add(t4+1, t7+1, t8);
+
+        double t9[2]; prod_1s_1s(a+1, a1_sp, b+1, b1_sp, t9);
+
+        double t10[2]; op<1,1>::add(t5+1, t9, t10);
+        double t11[2]; op<1,1>::add(t7, t10, t11);
+        r[2] = t11[0];
+        double t12[2]; op<1,1>::add(t8, t11+1, t12);
+        double t13[2]; op<1,1>::add(t8+1, t12+1, t13);
+        double t14[2]; op<1,1>::add(t9+1, t10+1, t14);
+        double t15[2]; op<1,1>::add(t12, t14, t15);
+        r[3] = t15[0];
+        double t16[2]; op<1,1>::add(t13, t15+1, t16);
+        double t17[2]; op<1,1>::add(t13+1, t16+1, t17);
+        double t18[2]; op<1,1>::add(t16, t14+1, t18);
+        r[4] = t18[0];
+        double t19[2]; op<1,1>::add(t17, t18+1, t19);
+        r[5] = t19[0];
+        double t20[2]; op<1,1>::add(t17+1, t19+1, t20);
+        r[6] = t20[0];
+        r[7] = t20[1];
+      }
+
+
+
+      static inline void square(const double a, double *r) {
+        r[1] = a * a;
+        double a_sp[2]; split(a, a_sp);
+        double err1 = r[1] - (a_sp[1] * a_sp[1]);
+        double err3 = err1 - ((a_sp[1] + a_sp[1]) * a_sp[0]);
+        r[0] = a_sp[0] * a_sp[0] - err3;
+      }
+
+      static inline void square_2(const double *a, double *r) {
+        double t1[2]; square(a[0], t1);
+        r[0] = t1[0];
+        double t2 = a[0] + a[0];
+        double t3[2]; prod_1_1(a+1, &t2, t3);
+        double t4[3]; op<2,1>::add(t3, t1 + 1, t4);
+        r[1] = t4[0];
+        double t5[2]; square(a[1], t5);
+        double t6[4]; op<2,2>::add(t5, t4 + 1, r + 2);
+      }
+    }
+
+
+
+    void exact_t::compress() {
+      double sum[2];
+
+      int j = size() - 1;
+      double Q = (*this)[j];
+      for (int i = (int)size()-2; i >= 0; --i) {
+        detail::op<1,1>::add_fast(&Q, &(*this)[i], sum);
+        if (sum[0] != 0) {
+          (*this)[j--] = sum[1];
+          Q = sum[0];
+        } else {
+          Q = sum[1];
+        }
+      }
+      int j2 = 0;
+      for (int i = j + 1; i < (int)size(); ++i) {
+        detail::op<1,1>::add_fast(&(*this)[i], &Q, sum);
+        if (sum[0] != 0) {
+          (*this)[j2++] = sum[0];
+        }
+        Q = sum[1];
+      }
+      (*this)[j2++] = Q;
+
+      erase(begin() + j2, end());
+    }
+
+    template<typename iter_t>
+    void negate(iter_t begin, iter_t end) {
+      while (begin != end) { *begin = -*begin; ++begin; }
+    }
+
+    void negate(exact_t &e) {
+      negate(&e[0], &e[e.size()]);
+    }
+
+    template<typename iter_t>
+    void scale_zeroelim(iter_t ebegin,
+                        iter_t eend,
+                        double b,
+                        exact_t &h) {
+      double Q;
+
+      h.clear();
+      double b_sp[2]; detail::split(b, b_sp);
+
+      double prod[2], sum[2];
+
+      detail::prod_1_1s((double *)ebegin++, &b, b_sp, prod);
+      Q = prod[1];
+      if (prod[0] != 0.0) {
+        h.push_back(prod[0]);
+      }
+      while (ebegin != eend) {
+        double enow = *ebegin++;
+        detail::prod_1_1s(&enow, &b, b_sp, prod);
+        detail::op<1,1>::add(&Q, prod, sum);
+        if (sum[0] != 0) {
+          h.push_back(sum[0]);
+        }
+        detail::op<1,1>::add_fast(prod+1, sum+1, sum);
+        Q = sum[1];
+        if (sum[0] != 0) {
+          h.push_back(sum[0]);
+        }
+      }
+      if ((Q != 0.0) || (h.size() == 0)) {
+        h.push_back(Q);
+      }
+    }
+
+    void scale_zeroelim(const exact_t &e,
+                        double b,
+                        exact_t &h) {
+      scale_zeroelim(&e[0], &e[e.size()], b, h);
+    }
+
+    template<typename iter_t>
+    void sum_zeroelim(iter_t ebegin,
+                      iter_t eend,
+                      iter_t fbegin,
+                      iter_t fend,
+                      exact_t &h) {
+      double Q;
+      double enow, fnow;
+
+      double sum[2];
+
+      enow = *ebegin;
+      fnow = *fbegin;
+
+      h.clear();
+
+      if ((fnow > enow) == (fnow > -enow)) {
+        Q = enow;
+        enow = *++ebegin;
+      } else {
+        Q = fnow;
+        fnow = *++fbegin;
+      }
+
+      if (ebegin != eend && fbegin != fend) {
+        if ((fnow > enow) == (fnow > -enow)) {
+          detail::op<1,1>::add_fast(&enow, &Q, sum);
+          enow = *++ebegin;
+        } else {
+          detail::op<1,1>::add_fast(&fnow, &Q, sum);
+          fnow = *++fbegin;
+        }
+        Q = sum[1];
+        if (sum[0] != 0.0) {
+          h.push_back(sum[0]);
+        }
+        while (ebegin != eend && fbegin != fend) {
+          if ((fnow > enow) == (fnow > -enow)) {
+            detail::op<1,1>::add(&Q, &enow, sum);
+            enow = *++ebegin;
+          } else {
+            detail::op<1,1>::add(&Q, &fnow, sum);
+            fnow = *++fbegin;
+          }
+          Q = sum[1];
+          if (sum[0] != 0.0) {
+            h.push_back(sum[0]);
+          }
+        }
+      }
+
+      while (ebegin != eend) {
+        detail::op<1,1>::add(&Q, &enow, sum);
+        enow = *++ebegin;
+        Q = sum[1];
+        if (sum[0] != 0.0) {
+          h.push_back(sum[0]);
+        }
+      }
+      while (fbegin != fend) {
+        detail::op<1,1>::add(&Q, &fnow, sum);
+        fnow = *++fbegin;
+        Q = sum[1];
+        if (sum[0] != 0.0) {
+          h.push_back(sum[0]);
+        }
+      }
+
+      if (Q != 0.0 || !h.size()) {
+        h.push_back(Q);
+      }
+    }
+
+    void sum_zeroelim(const exact_t &e,
+                      const exact_t &f,
+                      exact_t &h) {
+      sum_zeroelim(&e[0], &e[e.size()], &f[0], &f[f.size()], h);
+    }
+
+    void sum_zeroelim(const double *ebegin,
+                      const double *eend,
+                      const exact_t &f,
+                      exact_t &h) {
+      sum_zeroelim(ebegin, eend, &f[0], &f[f.size()], h);
+    }
+
+    void sum_zeroelim(const exact_t &e,
+                      const double *fbegin,
+                      const double *fend,
+                      exact_t &h) {
+      sum_zeroelim(&e[0], &e[e.size()], fbegin, fend, h);
+    }
+
+
+    // XXX: not implemented yet
+    //exact_t operator+(const exact_t &a, const exact_t &b) {
+    //}
+
+
+
+    void diffprod(const double a, const double b, const double c, const double d, double *r) {
+      // return ab - cd;
+      double ab[2], cd[2];
+      detail::prod_1_1(&a, &b, ab);
+      detail::prod_1_1(&c, &d, cd);
+      detail::op<2,2>::sub(ab, cd, r);
+    }
+
+    double orient3dexact(const double *pa,
+                         const double *pb,
+                         const double *pc,
+                         const double *pd) {
+      using namespace detail;
+
+      double ab[4]; diffprod(pa[0], pb[1], pb[0], pa[1], ab);
+      double bc[4]; diffprod(pb[0], pc[1], pc[0], pb[1], bc);
+      double cd[4]; diffprod(pc[0], pd[1], pd[0], pc[1], cd);
+      double da[4]; diffprod(pd[0], pa[1], pa[0], pd[1], da);
+      double ac[4]; diffprod(pa[0], pc[1], pc[0], pa[1], ac);
+      double bd[4]; diffprod(pb[0], pd[1], pd[0], pb[1], bd);
+
+      exact_t temp;
+      exact_t cda, dab, abc, bcd;
+      exact_t adet, bdet, cdet, ddet, abdet, cddet, det;
+
+      sum_zeroelim(cd, cd + 4, da, da + 4, temp);
+      sum_zeroelim(temp, ac, ac + 4, cda);
+
+      sum_zeroelim(da, da + 4, ab, ab + 4, temp);
+      sum_zeroelim(temp, bd, bd + 4, dab);
+
+      negate(bd, bd + 4);
+      negate(ac, bd + 4);
+
+      sum_zeroelim(ab, ab + 4, bc, bc + 4, temp);
+      sum_zeroelim(temp, ac, ac + 4, abc);
+
+      sum_zeroelim(bc, bc + 4, cd, cd + 4, temp);
+      sum_zeroelim(temp, bd, bd + 4, bcd);
+
+      scale_zeroelim(bcd, +pa[2], adet);
+      scale_zeroelim(cda, -pb[2], bdet);
+      scale_zeroelim(dab, +pc[2], cdet);
+      scale_zeroelim(abc, -pd[2], ddet);
+
+      sum_zeroelim(adet, bdet, abdet);
+      sum_zeroelim(cdet, ddet, cddet);
+
+      sum_zeroelim(abdet, cddet, det);
+  
+      return det[det.size() - 1];
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/face_decl.hpp b/extern/carve/include/carve/face_decl.hpp
new file mode 100644
index 00000000000..bc7afd44adc
--- /dev/null
+++ b/extern/carve/include/carve/face_decl.hpp
@@ -0,0 +1,208 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom2d.hpp>
+#include <carve/vector.hpp>
+#include <carve/matrix.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/aabb.hpp>
+#include <carve/tag.hpp>
+
+#include <vector>
+#include <list>
+#include <map>
+
+namespace carve {
+  namespace poly {
+
+
+
+    struct Object;
+
+    template<unsigned ndim>
+    class Edge;
+
+
+
+    template<unsigned ndim>
+    struct p2_adapt_project {
+      typedef carve::geom2d::P2 (*proj_t)(const carve::geom::vector<ndim> &);
+      proj_t proj;
+      p2_adapt_project(proj_t _proj) : proj(_proj) { }
+      carve::geom2d::P2 operator()(const carve::geom::vector<ndim> &v) const { return proj(v); }
+      carve::geom2d::P2 operator()(const carve::geom::vector<ndim> *v) const { return proj(*v); }
+      carve::geom2d::P2 operator()(const Vertex<ndim> &v) const { return proj(v.v); }
+      carve::geom2d::P2 operator()(const Vertex<ndim> *v) const { return proj(v->v); }
+    };
+
+
+    template<unsigned ndim>
+    class Face : public tagable {
+    public:
+      typedef Vertex<ndim> vertex_t;
+      typedef typename Vertex<ndim>::vector_t vector_t;
+      typedef Edge<ndim> edge_t;
+      typedef Object obj_t;
+      typedef carve::geom::aabb<ndim> aabb_t;
+      typedef carve::geom::plane<ndim> plane_t;
+
+      typedef carve::geom2d::P2 (*project_t)(const vector_t &);
+      typedef vector_t (*unproject_t)(const carve::geom2d::P2 &, const plane_t &);
+
+    protected:
+      std::vector<const vertex_t *> vertices; // pointer into polyhedron.vertices
+      std::vector<const edge_t *> edges; // pointer into polyhedron.edges
+
+      project_t getProjector(bool positive_facing, int axis);
+      unproject_t getUnprojector(bool positive_facing, int axis);
+
+    public:
+      typedef typename std::vector<const vertex_t *>::iterator vertex_iter_t;
+      typedef typename std::vector<const vertex_t *>::const_iterator const_vertex_iter_t;
+
+      typedef typename std::vector<const edge_t *>::iterator edge_iter_t;
+      typedef typename std::vector<const edge_t *>::const_iterator const_edge_iter_t;
+
+      obj_t *owner;
+
+      aabb_t aabb;
+      plane_t plane_eqn;
+      int manifold_id;
+      int group_id;
+
+      project_t project;
+      unproject_t unproject;
+
+      Face(const std::vector<const vertex_t *> &_vertices, bool delay_recalc = false);
+      Face(const vertex_t *v1, const vertex_t *v2, const vertex_t *v3, bool delay_recalc = false);
+      Face(const vertex_t *v1, const vertex_t *v2, const vertex_t *v3, const vertex_t *v4, bool delay_recalc = false);
+
+      template <typename iter_t>
+      Face(const Face *base, iter_t vbegin, iter_t vend, bool flipped) {
+        init(base, vbegin, vend, flipped);
+      }
+
+      Face(const Face *base, const std::vector<const vertex_t *> &_vertices, bool flipped) {
+        init(base, _vertices, flipped);
+      }
+
+      Face() {}
+      ~Face() {}
+
+      bool recalc();
+
+      template<typename iter_t>
+      Face *init(const Face *base, iter_t vbegin, iter_t vend, bool flipped);
+      Face *init(const Face *base, const std::vector<const vertex_t *> &_vertices, bool flipped);
+
+      template<typename iter_t>
+      Face *create(iter_t vbegin, iter_t vend, bool flipped) const;
+      Face *create(const std::vector<const vertex_t *> &_vertices, bool flipped) const;
+
+      Face *clone(bool flipped = false) const;
+      void invert();
+
+      void getVertexLoop(std::vector<const vertex_t *> &loop) const;
+
+      const vertex_t *&vertex(size_t idx);
+      const vertex_t *vertex(size_t idx) const;
+      size_t nVertices() const;
+
+      vertex_iter_t vbegin() { return vertices.begin(); }
+      vertex_iter_t vend() { return vertices.end(); }
+      const_vertex_iter_t vbegin() const { return vertices.begin(); }
+      const_vertex_iter_t vend() const { return vertices.end(); }
+
+      std::vector<carve::geom::vector<2> > projectedVertices() const;
+
+      const edge_t *&edge(size_t idx);
+      const edge_t *edge(size_t idx) const;
+      size_t nEdges() const;
+
+      edge_iter_t ebegin() { return edges.begin(); }
+      edge_iter_t eend() { return edges.end(); }
+      const_edge_iter_t ebegin() const { return edges.begin(); }
+      const_edge_iter_t eend() const { return edges.end(); }
+
+      bool containsPoint(const vector_t &p) const;
+      bool containsPointInProjection(const vector_t &p) const;
+      bool simpleLineSegmentIntersection(const carve::geom::linesegment<ndim> &line,
+                                         vector_t &intersection) const;
+      IntersectionClass lineSegmentIntersection(const carve::geom::linesegment<ndim> &line,
+                                                vector_t &intersection) const;
+      vector_t centroid() const;
+
+      p2_adapt_project<ndim> projector() const {
+        return p2_adapt_project<ndim>(project);
+      }
+
+      void swap(Face<ndim> &other);
+    };
+
+
+
+    struct hash_face_ptr {
+      template<unsigned ndim>
+      size_t operator()(const Face<ndim> * const &f) const {
+        return (size_t)f;
+      }
+    };
+
+
+
+    namespace face {
+
+
+
+      template<unsigned ndim>
+      static inline carve::geom2d::P2 project(const Face<ndim> *f, const typename Face<ndim>::vector_t &v) {
+        return f->project(v);
+      }
+
+
+
+      template<unsigned ndim>
+      static inline carve::geom2d::P2 project(const Face<ndim> &f, const typename Face<ndim>::vector_t &v) {
+        return f.project(v);
+      }
+
+
+
+      template<unsigned ndim>
+      static inline typename Face<ndim>::vector_t unproject(const Face<ndim> *f, const carve::geom2d::P2 &p) {
+        return f->unproject(p, f->plane_eqn);
+      }
+
+
+
+      template<unsigned ndim>
+      static inline typename Face<ndim>::vector_t unproject(const Face<ndim> &f, const carve::geom2d::P2 &p) {
+        return f.unproject(p, f.plane_eqn);
+      }
+
+
+
+    }
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/face_impl.hpp b/extern/carve/include/carve/face_impl.hpp
new file mode 100644
index 00000000000..771ba761111
--- /dev/null
+++ b/extern/carve/include/carve/face_impl.hpp
@@ -0,0 +1,140 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+namespace std {
+  template<unsigned ndim>
+  inline void swap(carve::poly::Face<ndim> &a, carve::poly::Face<ndim> &b) {
+    a.swap(b);
+  }
+}
+
+namespace carve {
+  namespace poly {
+    template<unsigned ndim>
+    void Face<ndim>::swap(Face<ndim> &other) {
+      std::swap(vertices,    other.vertices);
+      std::swap(edges,       other.edges);
+      std::swap(owner,       other.owner);
+      std::swap(aabb,        other.aabb);
+      std::swap(plane_eqn,   other.plane_eqn);
+      std::swap(manifold_id, other.manifold_id);
+      std::swap(group_id,    other.group_id);
+      std::swap(project,     other.project);
+      std::swap(unproject,   other.unproject);
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    Face<ndim> *Face<ndim>::init(const Face<ndim> *base, iter_t vbegin, iter_t vend, bool flipped) {
+      vertices.reserve(std::distance(vbegin, vend));
+
+      if (flipped) {
+        std::reverse_copy(vbegin, vend, std::back_inserter(vertices));
+        plane_eqn = -base->plane_eqn;
+      } else {
+        std::copy(vbegin, vend, std::back_inserter(vertices));
+        plane_eqn = base->plane_eqn;
+      }
+
+      edges.clear();
+      edges.resize(nVertices(), NULL);
+
+      aabb.fit(vertices.begin(), vertices.end(), vec_adapt_vertex_ptr());
+      untag();
+
+      int da = carve::geom::largestAxis(plane_eqn.N);
+
+      project = getProjector(plane_eqn.N.v[da] > 0, da);
+      unproject = getUnprojector(plane_eqn.N.v[da] > 0, da);
+
+      return this;
+    }
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    Face<ndim> *Face<ndim>::create(iter_t vbegin, iter_t vend, bool flipped) const {
+      return (new Face)->init(this, vbegin, vend, flipped);
+    }
+
+    template<unsigned ndim>
+    Face<ndim> *Face<ndim>::create(const std::vector<const vertex_t *> &_vertices, bool flipped) const {
+      return (new Face)->init(this, _vertices.begin(), _vertices.end(), flipped);
+    }
+
+    template<unsigned ndim>
+    Face<ndim> *Face<ndim>::clone(bool flipped) const {
+      return (new Face)->init(this, vertices, flipped);
+    }
+
+    template<unsigned ndim>
+    void Face<ndim>::getVertexLoop(std::vector<const vertex_t *> &loop) const {
+      loop.resize(nVertices(), NULL);
+      std::copy(vbegin(), vend(), loop.begin());
+    }
+
+    template<unsigned ndim>
+    const typename Face<ndim>::edge_t *&Face<ndim>::edge(size_t idx) {
+      return edges[idx];
+    }
+
+    template<unsigned ndim>
+    const typename Face<ndim>::edge_t *Face<ndim>::edge(size_t idx) const {
+      return edges[idx];
+    }
+
+    template<unsigned ndim>
+    size_t Face<ndim>::nEdges() const {
+      return edges.size();
+    }
+
+    template<unsigned ndim>
+    const typename Face<ndim>::vertex_t *&Face<ndim>::vertex(size_t idx) {
+      return vertices[idx];
+    }
+
+    template<unsigned ndim>
+    const typename Face<ndim>::vertex_t *Face<ndim>::vertex(size_t idx) const {
+      return vertices[idx];
+    }
+
+    template<unsigned ndim>
+    size_t Face<ndim>::nVertices() const {
+      return vertices.size();
+    }
+
+    template<unsigned ndim>
+    typename Face<ndim>::vector_t Face<ndim>::centroid() const {
+      vector_t c;
+      carve::geom::centroid(vertices.begin(), vertices.end(), vec_adapt_vertex_ptr(), c);
+      return c;
+    }
+
+    template<unsigned ndim>
+    std::vector<carve::geom::vector<2> > Face<ndim>::projectedVertices() const {
+      p2_adapt_project<ndim> proj = projector();
+      std::vector<carve::geom::vector<2> > result;
+      result.reserve(nVertices());
+      for (size_t i = 0; i < nVertices(); ++i) {
+        result.push_back(proj(vertex(i)->v));
+      }
+      return result;
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/faceloop.hpp b/extern/carve/include/carve/faceloop.hpp
new file mode 100644
index 00000000000..5df1d2080f3
--- /dev/null
+++ b/extern/carve/include/carve/faceloop.hpp
@@ -0,0 +1,103 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/classification.hpp>
+#include <carve/collection_types.hpp>
+
+namespace carve {
+  namespace csg {
+
+    struct FaceLoopGroup;
+
+    struct FaceLoop {
+      FaceLoop *next, *prev;
+      const carve::mesh::MeshSet<3>::face_t *orig_face;
+      std::vector<carve::mesh::MeshSet<3>::vertex_t *> vertices;
+      FaceLoopGroup *group;
+
+      FaceLoop(const carve::mesh::MeshSet<3>::face_t *f, const std::vector<carve::mesh::MeshSet<3>::vertex_t *> &v) : next(NULL), prev(NULL), orig_face(f), vertices(v), group(NULL) {}
+    };
+
+
+    struct FaceLoopList {
+      FaceLoop *head, *tail;
+      unsigned count;
+
+      FaceLoopList() : head(NULL), tail(NULL), count(0) { }
+
+      void append(FaceLoop *f) {
+        f->prev = tail;
+        f->next = NULL;
+        if (tail) tail->next = f;
+        tail = f;
+        if (!head) head = f;
+        count++;
+      }
+
+      void prepend(FaceLoop *f) {
+        f->next = head;
+        f->prev = NULL;
+        if (head) head->prev = f;
+        head = f;
+        if (!tail) tail = f;
+        count++;
+      }
+
+      unsigned size() const {
+        return count;
+      }
+
+      FaceLoop *remove(FaceLoop *f) {
+        FaceLoop *r = f->next;
+        if (f->prev) { f->prev->next = f->next; } else { head = f->next; }
+        if (f->next) { f->next->prev = f->prev; } else { tail = f->prev; }
+        f->next = f->prev = NULL;
+        count--;
+        return r;
+      }
+
+      ~FaceLoopList() {
+        FaceLoop *a = head, *b;
+        while (a) {
+          b = a;
+          a = a->next;
+          delete b;
+        }
+      }
+    };
+
+    struct FaceLoopGroup {
+      const carve::mesh::MeshSet<3> *src;
+      FaceLoopList face_loops;
+      V2Set perimeter;
+      std::list<ClassificationInfo> classification;
+
+      FaceLoopGroup(const carve::mesh::MeshSet<3> *_src) : src(_src) {
+      }
+
+      FaceClass classificationAgainst(const carve::mesh::MeshSet<3>::mesh_t *mesh) const;
+    };
+
+
+
+    typedef std::list<FaceLoopGroup> FLGroupList;
+
+  }
+}
diff --git a/extern/carve/include/carve/geom.hpp b/extern/carve/include/carve/geom.hpp
new file mode 100644
index 00000000000..421083e3e3c
--- /dev/null
+++ b/extern/carve/include/carve/geom.hpp
@@ -0,0 +1,363 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <vector>
+
+namespace carve {
+  namespace geom {
+
+    template<unsigned ndim> struct aabb;
+
+    // ========================================================================
+    struct _uninitialized { };
+
+    template<unsigned ndim>
+    struct base {
+      double v[ndim];
+    };
+
+    template<> struct base<2> {union { double v[2]; struct { double x, y; }; }; };
+    template<> struct base<3> {union { double v[3]; struct { double x, y, z; }; }; };
+    template<> struct base<4> {union { double v[4]; struct { double x, y, z, w; }; }; };
+
+    template<unsigned ndim>
+    struct vector : public base<ndim> {
+      enum { __ndim = ndim };
+
+      static vector ZERO();
+      double length2() const;
+      double length() const;
+      vector<ndim> &normalize();
+      vector<ndim> normalized() const;
+      bool exactlyZero() const;
+      bool isZero(double epsilon = EPSILON) const;
+      void setZero();
+      void fill(double val);
+      vector<ndim> &scaleBy(double d);
+      vector<ndim> &invscaleBy(double d);
+      vector<ndim> scaled(double d) const;
+      vector<ndim> invscaled(double d) const;
+      vector<ndim> &negate();
+      vector<ndim> negated() const;
+      double &operator[](unsigned i);
+      const double &operator[](unsigned i) const;
+      template<typename assign_t>
+      vector<ndim> &operator=(const assign_t &t);
+      std::string asStr() const;
+
+      aabb<ndim> getAABB() const;
+
+      vector() { setZero(); }
+      vector(noinit_t) { }
+    };
+
+    template<unsigned ndim>
+    vector<ndim> vector<ndim>::ZERO() { vector<ndim> r; r.setZero(); return r; }
+
+    static inline vector<2> VECTOR(double x, double y) { vector<2> r; r.x = x; r.y = y; return r; }
+    static inline vector<3> VECTOR(double x, double y, double z) { vector<3> r; r.x = x; r.y = y; r.z = z; return r; }
+    static inline vector<4> VECTOR(double x, double y, double z, double w) { vector<4> r; r.x = x; r.y = y; r.z = z; r.w = w; return r; }
+
+    template<unsigned ndim> vector<ndim> operator+(const vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> vector<ndim> operator+(const vector<ndim> &a, double b);
+    template<unsigned ndim, typename val_t> vector<ndim> operator+(const vector<ndim> &a, const val_t &b);
+    template<unsigned ndim, typename val_t> vector<ndim> operator+(const val_t &a, const vector<ndim> &b);
+
+    template<unsigned ndim> vector<ndim> &operator+=(vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> vector<ndim> &operator+=(vector<ndim> &a, double b);
+    template<unsigned ndim, typename val_t> vector<ndim> &operator+=(vector<ndim> &a, const val_t &b);
+
+    template<unsigned ndim> vector<ndim> operator-(const vector<ndim> &a);
+
+    template<unsigned ndim> vector<ndim> operator-(const vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> vector<ndim> operator-(const vector<ndim> &a, double b);
+    template<unsigned ndim, typename val_t> vector<ndim> operator-(const vector<ndim> &a, const val_t &b);
+    template<unsigned ndim, typename val_t> vector<ndim> operator-(const val_t &a, const vector<ndim> &b);
+
+    template<unsigned ndim> vector<ndim> &operator-=(vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> vector<ndim> &operator-=(vector<ndim> &a, double b);
+    template<unsigned ndim, typename val_t> vector<ndim> &operator-=(vector<ndim> &a, const val_t &b);
+
+    template<unsigned ndim> vector<ndim> operator*(const vector<ndim> &a, double s);
+    template<unsigned ndim> vector<ndim> operator*(double s, const vector<ndim> &a);
+    template<unsigned ndim> vector<ndim> &operator*=(vector<ndim> &a, double s);
+
+    template<unsigned ndim> vector<ndim> operator/(const vector<ndim> &a, double s);
+    template<unsigned ndim> vector<ndim> &operator/=(vector<ndim> &a, double s);
+
+    template<unsigned ndim> bool operator==(const vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator!=(const vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator<(const vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator<=(const vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator>(const vector<ndim> &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator>=(const vector<ndim> &a, const vector<ndim> &b);
+
+    template<unsigned ndim> vector<ndim> abs(const vector<ndim> &a);
+
+    template<unsigned ndim> double distance2(const vector<ndim> &a, const vector<ndim> &b);
+
+    template<unsigned ndim> double distance(const vector<ndim> &a, const vector<ndim> &b);
+
+    template<unsigned ndim> bool equal(const vector<ndim> &a, const vector<ndim> &b);
+
+    template<unsigned ndim> int smallestAxis(const vector<ndim> &a);
+
+    template<unsigned ndim> int largestAxis(const vector<ndim> &a);
+
+    template<unsigned ndim> vector<2> select(const vector<ndim> &a, int a1, int a2);
+
+    template<unsigned ndim> vector<3> select(const vector<ndim> &a, int a1, int a2, int a3);
+
+    template<unsigned ndim, typename assign_t, typename oper_t>
+    vector<ndim> &assign_op(vector<ndim> &a, const assign_t &t, oper_t op);
+
+    template<unsigned ndim, typename assign1_t, typename assign2_t, typename oper_t>
+    vector<ndim> &assign_op(vector<ndim> &a, const assign1_t &t1, const assign2_t &t2, oper_t op);
+
+    template<unsigned ndim, typename iter_t>
+    void bounds(iter_t begin, iter_t end, vector<ndim> &min, vector<ndim> &max);
+
+    template<unsigned ndim, typename iter_t, typename adapt_t>
+    void bounds(iter_t begin, iter_t end, adapt_t adapt, vector<ndim> &min, vector<ndim> &max);
+
+    template<unsigned ndim, typename iter_t, typename adapt_t>
+    void centroid(iter_t begin, iter_t end, adapt_t adapt, vector<ndim> &c);
+
+    template<unsigned ndim, typename val_t> double dot(const vector<ndim> &a, const val_t &b);
+
+    static inline vector<3> cross(const vector<3> &a, const vector<3> &b);
+
+    static inline double cross(const vector<2> &a, const vector<2> &b);
+
+    static inline double dotcross(const vector<3> &a, const vector<3> &b, const vector<3> &c);
+
+
+
+    // ========================================================================
+    struct axis_pos {
+      int axis;
+      double pos;
+
+      axis_pos(int _axis, double _pos) : axis(_axis), pos(_pos) { }
+    };
+
+    template<unsigned ndim>
+    double distance(const axis_pos &a, const vector<ndim> &b);
+
+    template<unsigned ndim>
+    double distance2(const axis_pos &a, const vector<ndim> &b);
+
+    template<unsigned ndim> bool operator<(const axis_pos &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator<(const vector<ndim> &a, const axis_pos &b);
+
+    template<unsigned ndim> bool operator<=(const axis_pos &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator<=(const vector<ndim> &a, const axis_pos &b);
+
+    template<unsigned ndim> bool operator>(const axis_pos &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator>(const vector<ndim> &a, const axis_pos &b);
+
+    template<unsigned ndim> bool operator>=(const axis_pos &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator>=(const vector<ndim> &a, const axis_pos &b);
+
+    template<unsigned ndim> bool operator==(const axis_pos &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator==(const vector<ndim> &a, const axis_pos &b);
+
+    template<unsigned ndim> bool operator!=(const axis_pos &a, const vector<ndim> &b);
+    template<unsigned ndim> bool operator!=(const vector<ndim> &a, const axis_pos &b);
+
+
+
+    // ========================================================================
+    template<unsigned ndim>
+    struct ray {
+      typedef vector<ndim> vector_t;
+
+      vector_t D, v;
+
+      bool OK() const;
+
+      ray() { }
+      ray(vector_t _D, vector_t _v) : D(_D), v(_v) { }
+    };
+
+    template<unsigned ndim>
+    ray<ndim> rayThrough(const vector<ndim> &a, const vector<ndim> &b);
+
+    static inline double distance2(const ray<3> &r, const vector<3> &v);
+
+    static inline double distance(const ray<3> &r, const vector<3> &v);
+
+    static inline double distance2(const ray<2> &r, const vector<2> &v);
+
+    static inline double distance(const ray<2> &r, const vector<2> &v);
+
+
+
+    // ========================================================================
+    template<unsigned ndim>
+    struct linesegment {
+      typedef vector<ndim> vector_t;
+
+      vector_t v1;
+      vector_t v2;
+      vector_t midpoint;
+      vector_t half_length;
+
+      void update();
+      bool OK() const;
+      void flip();
+
+      aabb<ndim> getAABB() const;
+
+      linesegment(const vector_t &_v1, const vector_t &_v2);
+    };
+
+    template<unsigned ndim>
+    double distance2(const linesegment<ndim> &l, const vector<ndim> &v);
+
+    template<unsigned ndim>
+    double distance(const linesegment<ndim> &l, const vector<ndim> &v);
+
+
+
+    // ========================================================================
+    template<unsigned ndim>
+    struct plane {
+      typedef vector<ndim> vector_t;
+
+      vector_t N;
+      double d;
+
+      void negate();
+
+      plane();
+      plane(const vector_t &_N, vector_t _p);
+      plane(const vector_t &_N, double _d);
+    };
+
+    template<unsigned ndim>
+    inline plane<ndim> operator-(const plane<ndim> &p);
+
+    template<unsigned ndim, typename val_t>
+    double distance(const plane<ndim> &plane, const val_t &point);
+
+    template<unsigned ndim, typename val_t>
+    double distance2(const plane<ndim> &plane, const val_t &point);
+
+    template<unsigned ndim>
+    static inline vector<ndim> closestPoint(const plane<ndim> &p, const vector<ndim> &v);
+
+
+
+    // ========================================================================
+    template<unsigned ndim>
+    struct sphere {
+      typedef vector<ndim> vector_t;
+
+      vector_t C;
+      double r;
+
+      aabb<ndim> getAABB() const;
+
+      sphere();
+      sphere(const vector_t &_C, double _r);
+    };
+
+    template<unsigned ndim, typename val_t>
+    double distance(const sphere<ndim> &sphere, const val_t &point);
+
+    template<unsigned ndim, typename val_t>
+    double distance2(const sphere<ndim> &sphere, const val_t &point);
+
+    template<unsigned ndim>
+    static inline vector<ndim> closestPoint(const sphere<ndim> &sphere, const vector<ndim> &point);
+
+
+    // ========================================================================
+    template<unsigned ndim>
+    struct tri {
+      typedef vector<ndim> vector_t;
+
+      vector_t v[3];
+
+      aabb<ndim> getAABB() const;
+
+      tri(vector_t _v[3]);
+      tri(const vector_t &a, const vector_t &b, const vector_t &c);
+
+      vector_t normal() const {
+        return cross(v[1] - v[0], v[2] - v[1]).normalized();
+      }
+    };
+
+
+
+    template<unsigned ndim> std::ostream &operator<<(std::ostream &o, const vector<ndim> &v);
+    template<unsigned ndim> std::ostream &operator<<(std::ostream &o, const carve::geom::plane<ndim> &p);
+    template<unsigned ndim> std::ostream &operator<<(std::ostream &o, const carve::geom::sphere<ndim> &sphere);
+    template<unsigned ndim> std::ostream &operator<<(std::ostream &o, const carve::geom::tri<ndim> &tri);
+
+
+
+    template<unsigned ndim> vector<ndim> closestPoint(const tri<ndim> &tri, const vector<ndim> &pt);
+    template<unsigned ndim> double distance(const tri<ndim> &tri, const vector<ndim> &pt);
+    template<unsigned ndim> double distance2(const tri<ndim> &tri, const vector<ndim> &pt);
+
+
+
+    // ========================================================================
+    struct distance_functor {
+      template<typename obj1_t, typename obj2_t>
+      double operator()(const obj1_t &o1, const obj2_t &o2) {
+        return distance(o1, o2);
+      }
+    };
+
+
+
+    // ========================================================================
+    template<int base, int power> struct __pow__          { enum { val = __pow__<base, (power >> 1)>::val * __pow__<base, power - (power >> 1)>::val }; };
+    template<int base>            struct __pow__<base, 1> { enum { val = base }; };
+    template<int base>            struct __pow__<base, 0> { enum { val = 1 }; };
+
+    template<unsigned base, unsigned ndigits>
+    struct quantize {
+      typedef __pow__<base, ndigits> fac;
+
+      double operator()(double in) {
+        return round(in * fac::val) / fac::val;
+      }
+
+      template<unsigned ndim>
+      vector<ndim> operator()(const vector<ndim> &in) {
+        vector<ndim> r(NOINIT);
+        assign_op(r, in, *this);
+        return r;
+      }
+    };
+
+
+
+  }
+}
+
+
+#include <carve/geom_impl.hpp>
diff --git a/extern/carve/include/carve/geom2d.hpp b/extern/carve/include/carve/geom2d.hpp
new file mode 100644
index 00000000000..731e22919b6
--- /dev/null
+++ b/extern/carve/include/carve/geom2d.hpp
@@ -0,0 +1,403 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/math.hpp>
+#include <carve/math_constants.hpp>
+
+#include <carve/geom.hpp>
+
+#include <vector>
+#include <algorithm>
+
+#include <math.h>
+
+#if defined(CARVE_DEBUG)
+#  include <iostream>
+#endif
+
+#if defined CARVE_USE_EXACT_PREDICATES
+#  include <carve/shewchuk_predicates.hpp>
+#endif
+
+namespace carve {
+  namespace geom2d {
+
+    typedef carve::geom::vector<2> P2;
+    typedef carve::geom::ray<2> Ray2;
+    typedef carve::geom::linesegment<2> LineSegment2;
+
+
+
+    struct p2_adapt_ident {
+      P2 &operator()(P2 &p) const { return p; }
+      const P2 &operator()(const P2 &p) const { return p; }
+    };
+
+
+
+    typedef std::vector<P2> P2Vector;
+
+    /** 
+     * \brief Return the orientation of c with respect to the ray defined by a->b.
+     *
+     * (Can be implemented exactly)
+     * 
+     * @param[in] a 
+     * @param[in] b 
+     * @param[in] c 
+     * 
+     * @return positive, if c to the left of a->b.
+     *         zero, if c is colinear with a->b.
+     *         negative, if c to the right of a->b.
+     */
+#if defined CARVE_USE_EXACT_PREDICATES
+    inline double orient2d(const P2 &a, const P2 &b, const P2 &c) {
+      return shewchuk::orient2d(a.v, b.v, c.v);
+    }
+#else
+    inline double orient2d(const P2 &a, const P2 &b, const P2 &c) {
+      double acx = a.x - c.x;
+      double bcx = b.x - c.x;
+      double acy = a.y - c.y;
+      double bcy = b.y - c.y;
+      return acx * bcy - acy * bcx;
+    }
+#endif
+
+    /** 
+     * \brief Determine whether p is internal to the anticlockwise
+     *        angle abc, where b is the apex of the angle.
+     *
+     * @param[in] a 
+     * @param[in] b 
+     * @param[in] c 
+     * @param[in] p 
+     * 
+     * @return true, if p is contained in the anticlockwise angle from
+     *               b->a to b->c. Reflex angles contain p if p lies
+     *               on b->a or on b->c. Acute angles do not contain p
+     *               if p lies on b->a or on b->c. This is so that
+     *               internalToAngle(a,b,c,p) = !internalToAngle(c,b,a,p)
+     */
+    inline bool internalToAngle(const P2 &a,
+                                const P2 &b,
+                                const P2 &c,
+                                const P2 &p) {
+      bool reflex = (a < c) ?  orient2d(b, a, c) <= 0.0 : orient2d(b, c, a) > 0.0;
+      double d1 = orient2d(b, a, p);
+      double d2 = orient2d(b, c, p);
+      if (reflex) {
+        return d1 >= 0.0 || d2 <= 0.0;
+      } else {
+        return d1 > 0.0 && d2 < 0.0;
+      }
+    }
+
+    /** 
+     * \brief Determine whether p is internal to the anticlockwise
+     *        angle ac, with apex at (0,0).
+     *
+     * @param[in] a 
+     * @param[in] c 
+     * @param[in] p 
+     * 
+     * @return true, if p is contained in a0c.
+     */
+    inline bool internalToAngle(const P2 &a,
+                                const P2 &c,
+                                const P2 &p) {
+      return internalToAngle(a, P2::ZERO(), c, p);
+    }
+
+    template<typename P2vec>
+    bool isAnticlockwise(const P2vec &tri) {
+      return orient2d(tri[0], tri[1], tri[2]) > 0.0;
+    }
+
+    template<typename P2vec>
+    bool pointIntersectsTriangle(const P2 &p, const P2vec &tri) {
+      int orient = isAnticlockwise(tri) ? +1 : -1;
+      if (orient2d(tri[0], tri[1], p) * orient < 0) return false;
+      if (orient2d(tri[1], tri[2], p) * orient < 0) return false;
+      if (orient2d(tri[2], tri[0], p) * orient < 0) return false;
+      return true;
+    }
+
+    template<typename P2vec>
+    bool lineIntersectsTriangle(const P2 &p1, const P2 &p2, const P2vec &tri) {
+      double s[3];
+      // does tri lie on one side or the other of p1-p2?
+      s[0] = orient2d(p1, p2, tri[0]);
+      s[1] = orient2d(p1, p2, tri[1]);
+      s[2] = orient2d(p1, p2, tri[2]);
+      if (*std::max_element(s, s+3) < 0) return false;
+      if (*std::min_element(s, s+3) > 0) return false;
+
+      // does line lie entirely to the right of a triangle edge?
+      int orient = isAnticlockwise(tri) ? +1 : -1;
+      if (orient2d(tri[0], tri[1], p1) * orient < 0 && orient2d(tri[0], tri[1], p2) * orient < 0) return false;
+      if (orient2d(tri[1], tri[2], p1) * orient < 0 && orient2d(tri[1], tri[2], p2) * orient < 0) return false;
+      if (orient2d(tri[2], tri[0], p1) * orient < 0 && orient2d(tri[2], tri[0], p2) * orient < 0) return false;
+      return true;
+    }
+
+    template<typename P2vec>
+    int triangleLineOrientation(const P2 &p1, const P2 &p2, const P2vec &tri) {
+      double lo, hi, tmp;
+      lo = hi = orient2d(p1, p2, tri[0]);
+      tmp = orient2d(p1, p2, tri[1]); lo = std::min(lo, tmp); hi = std::max(hi, tmp);
+      tmp = orient2d(p1, p2, tri[2]); lo = std::min(lo, tmp); hi = std::max(hi, tmp);
+      if (hi < 0.0) return -1;
+      if (lo > 0.0) return +1;
+      return 0;
+    }
+
+    template<typename P2vec>
+    bool triangleIntersectsTriangle(const P2vec &tri_b, const P2vec &tri_a) {
+      int orient_a = isAnticlockwise(tri_a) ? +1 : -1;
+      if (triangleLineOrientation(tri_a[0], tri_a[1], tri_b) * orient_a < 0) return false;
+      if (triangleLineOrientation(tri_a[1], tri_a[2], tri_b) * orient_a < 0) return false;
+      if (triangleLineOrientation(tri_a[2], tri_a[0], tri_b) * orient_a < 0) return false;
+
+      int orient_b = isAnticlockwise(tri_b) ? +1 : -1;
+      if (triangleLineOrientation(tri_b[0], tri_b[1], tri_a) * orient_b < 0) return false;
+      if (triangleLineOrientation(tri_b[1], tri_b[2], tri_a) * orient_b < 0) return false;
+      if (triangleLineOrientation(tri_b[2], tri_b[0], tri_a) * orient_b < 0) return false;
+
+      return true;
+    }
+
+
+
+    static inline double atan2(const P2 &p) {
+      return ::atan2(p.y, p.x);
+    }
+
+
+
+    struct LineIntersectionInfo {
+      LineIntersectionClass iclass;
+      P2 ipoint;
+      int p1, p2;
+
+      LineIntersectionInfo(LineIntersectionClass _iclass,
+                           P2 _ipoint = P2::ZERO(),
+                           int _p1 = -1,
+                           int _p2 = -1) :
+        iclass(_iclass), ipoint(_ipoint), p1(_p1), p2(_p2) {
+      }
+    };
+
+    struct PolyInclusionInfo {
+      PointClass iclass;
+      int iobjnum;
+
+      PolyInclusionInfo(PointClass _iclass,
+                        int _iobjnum = -1) :
+        iclass(_iclass), iobjnum(_iobjnum) {
+      }
+    };
+
+    struct PolyIntersectionInfo {
+      IntersectionClass iclass;
+      P2 ipoint;
+      size_t iobjnum;
+
+      PolyIntersectionInfo(IntersectionClass _iclass,
+                           const P2 &_ipoint,
+                           size_t _iobjnum) :
+        iclass(_iclass), ipoint(_ipoint), iobjnum(_iobjnum) {
+      }
+    };
+
+    bool lineSegmentIntersection_simple(const P2 &l1v1, const P2 &l1v2,
+                                        const P2 &l2v1, const P2 &l2v2);
+    bool lineSegmentIntersection_simple(const LineSegment2 &l1,
+                                        const LineSegment2 &l2);
+
+    LineIntersectionInfo lineSegmentIntersection(const P2 &l1v1, const P2 &l1v2,
+                                                 const P2 &l2v1, const P2 &l2v2);
+    LineIntersectionInfo lineSegmentIntersection(const LineSegment2 &l1,
+                                                 const LineSegment2 &l2);
+
+    int lineSegmentPolyIntersections(const std::vector<P2> &points,
+                                     LineSegment2 line,
+                                     std::vector<PolyInclusionInfo> &out);
+
+    int sortedLineSegmentPolyIntersections(const std::vector<P2> &points,
+                                           LineSegment2 line,
+                                           std::vector<PolyInclusionInfo> &out);
+
+
+
+    static inline bool quadIsConvex(const P2 &a, const P2 &b, const P2 &c, const P2 &d) {
+      double s_1, s_2;
+
+      s_1 = carve::geom2d::orient2d(a, c, b);
+      s_2 = carve::geom2d::orient2d(a, c, d);
+      if ((s_1 < 0.0 && s_2 < 0.0) || (s_1 > 0.0 && s_2 > 0.0)) return false;
+
+      s_1 = carve::geom2d::orient2d(b, d, a);
+      s_2 = carve::geom2d::orient2d(b, d, c);
+      if ((s_1 < 0.0 && s_2 < 0.0) || (s_1 > 0.0 && s_2 > 0.0)) return false;
+
+      return true;
+    }
+
+    template<typename T, typename adapt_t>
+    inline bool quadIsConvex(const T &a, const T &b, const T &c, const T &d, adapt_t adapt) {
+      return quadIsConvex(adapt(a), adapt(b), adapt(c), adapt(d));
+    }
+
+
+
+    double signedArea(const std::vector<P2> &points);
+
+    static inline double signedArea(const P2 &a, const P2 &b, const P2 &c) {
+      return ((b.y + a.y) * (b.x - a.x) + (c.y + b.y) * (c.x - b.x) + (a.y + c.y) * (a.x - c.x)) / 2.0;
+    }
+
+    template<typename T, typename adapt_t>
+    double signedArea(const std::vector<T> &points, adapt_t adapt) {
+      P2Vector::size_type l = points.size();
+      double A = 0.0;
+
+      for (P2Vector::size_type i = 0; i < l - 1; i++) {
+        A += (adapt(points[i + 1]).y + adapt(points[i]).y) * (adapt(points[i + 1]).x - adapt(points[i]).x);
+      }
+      A += (adapt(points[0]).y + adapt(points[l - 1]).y) * (adapt(points[0]).x - adapt(points[l - 1]).x);
+
+      return A / 2.0;
+    }
+
+
+
+    template<typename iter_t, typename adapt_t>
+    double signedArea(iter_t begin, iter_t end, adapt_t adapt) {
+      double A = 0.0;
+      P2 p, n;
+
+      if (begin == end) return 0.0;
+
+      p = adapt(*begin);
+      for (iter_t c = begin; ++c != end; ) {
+        P2 n = adapt(*c);
+        A += (n.y + p.y) * (n.x - p.x);
+        p = n;
+      }
+      n = adapt(*begin);
+      A += (n.y + p.y) * (n.x - p.x);
+
+      return A / 2.0;
+    }
+
+
+
+    bool pointInPolySimple(const std::vector<P2> &points, const P2 &p);
+
+    template<typename T, typename adapt_t>
+    bool pointInPolySimple(const std::vector<T> &points, adapt_t adapt, const P2 &p) {
+      CARVE_ASSERT(points.size() > 0);
+      P2Vector::size_type l = points.size();
+      double s = 0.0;
+      double rp, r0, d;
+
+      rp = r0 = atan2(adapt(points[0]) - p);
+
+      for (P2Vector::size_type i = 1; i < l; i++) {
+        double r = atan2(adapt(points[i]) - p);
+        d = r - rp;
+        if (d > M_PI) d -= M_TWOPI;
+        if (d < -M_PI) d += M_TWOPI;
+        s = s + d;
+        rp = r;
+      }
+
+      d = r0 - rp;
+      if (d > M_PI) d -= M_TWOPI;
+      if (d < -M_PI) d += M_TWOPI;
+      s = s + d;
+
+      return !carve::math::ZERO(s);
+    }
+
+
+
+    PolyInclusionInfo pointInPoly(const std::vector<P2> &points, const P2 &p);
+
+    template<typename T, typename adapt_t>
+    PolyInclusionInfo pointInPoly(const std::vector<T> &points, adapt_t adapt, const P2 &p) {
+      P2Vector::size_type l = points.size();
+      for (unsigned i = 0; i < l; i++) {
+        if (equal(adapt(points[i]), p)) return PolyInclusionInfo(POINT_VERTEX, i);
+      }
+
+      for (unsigned i = 0; i < l; i++) {
+        unsigned j = (i + 1) % l;
+
+        if (std::min(adapt(points[i]).x, adapt(points[j]).x) - EPSILON < p.x &&
+            std::max(adapt(points[i]).x, adapt(points[j]).x) + EPSILON > p.x &&
+            std::min(adapt(points[i]).y, adapt(points[j]).y) - EPSILON < p.y &&
+            std::max(adapt(points[i]).y, adapt(points[j]).y) + EPSILON > p.y &&
+            distance2(carve::geom::rayThrough(adapt(points[i]), adapt(points[j])), p) < EPSILON2) {
+          return PolyInclusionInfo(POINT_EDGE, i);
+        }
+      }
+
+      if (pointInPolySimple(points, adapt, p)) {
+        return PolyInclusionInfo(POINT_IN);
+      }
+
+      return PolyInclusionInfo(POINT_OUT);
+    }
+
+
+
+    bool pickContainedPoint(const std::vector<P2> &poly, P2 &result);
+
+    template<typename T, typename adapt_t>
+    bool pickContainedPoint(const std::vector<T> &poly, adapt_t adapt, P2 &result) {
+#if defined(CARVE_DEBUG)
+      std::cerr << "pickContainedPoint ";
+      for (unsigned i = 0; i < poly.size(); ++i) std::cerr << " " << adapt(poly[i]);
+      std::cerr << std::endl;
+#endif
+
+      const size_t S = poly.size();
+      P2 a, b, c;
+      for (unsigned i = 0; i < S; ++i) {
+        a = adapt(poly[i]);
+        b = adapt(poly[(i + 1) % S]);
+        c = adapt(poly[(i + 2) % S]);
+
+        if (cross(a - b, c - b) < 0) {
+          P2 p = (a + b + c) / 3;
+          if (pointInPolySimple(poly, adapt, p)) {
+            result = p;
+            return true;
+          }
+        }
+      }
+      return false;
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/geom3d.hpp b/extern/carve/include/carve/geom3d.hpp
new file mode 100644
index 00000000000..90d0672b81e
--- /dev/null
+++ b/extern/carve/include/carve/geom3d.hpp
@@ -0,0 +1,310 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/geom.hpp>
+
+#include <math.h>
+#include <carve/math_constants.hpp>
+
+#include <vector>
+#include <list>
+#include <map>
+
+#if defined(CARVE_DEBUG)
+#  include <iostream>
+#endif
+
+#if defined CARVE_USE_EXACT_PREDICATES
+#  include <carve/shewchuk_predicates.hpp>
+#endif
+
+namespace carve {
+  namespace geom3d {
+
+    typedef carve::geom::plane<3> Plane;
+    typedef carve::geom::ray<3> Ray;
+    typedef carve::geom::linesegment<3> LineSegment;
+    typedef carve::geom::vector<3> Vector;
+
+    template<typename iter_t, typename adapt_t>
+    bool fitPlane(iter_t begin, iter_t end, adapt_t adapt, Plane &plane) {
+      Vector centroid;
+      carve::geom::centroid(begin, end, adapt, centroid);
+      iter_t i;
+
+      Vector n = Vector::ZERO();
+      Vector v;
+      Vector p1, p2, p3, c1, c2;
+      if (begin == end) return false;
+
+      i = begin;
+      p1 = c1 = adapt(*i); if (++i == end) return false;
+      p2 = c2 = adapt(*i); if (++i == end) return false;
+
+#if defined(CARVE_DEBUG)
+      size_t N = 2;
+#endif
+      do {
+        p3 = adapt(*i);
+        v = cross(p3 - p2, p1 - p2);
+        if (v.v[largestAxis(v)]) v.negate();
+        n += v;
+        p1 = p2; p2 = p3;
+#if defined(CARVE_DEBUG)
+        ++N;
+#endif
+      } while (++i != end);
+
+      p1 = p2; p2 = p3; p3 = c1;
+      v = cross(p3 - p2, p1 - p2);
+      if (v.v[largestAxis(v)]) v.negate();
+      n += v;
+
+      p1 = p2; p2 = p3; p3 = c2;
+      v = cross(p3 - p2, p1 - p2);
+      if (v.v[largestAxis(v)]) v.negate();
+      n += v;
+
+      n.normalize();
+      plane.N = n;
+      plane.d = -dot(n, centroid);
+#if defined(CARVE_DEBUG)
+      if (N > 3) {
+        std::cerr << "N = " << N << " fitted distance:";
+        for (i = begin; i != end; ++i) {
+          Vector p = adapt(*i);
+          std::cerr << " {" << p << "} " << distance(plane, p);
+        }
+        std::cerr << std::endl;
+      }
+#endif
+      return true;
+    }
+
+    bool planeIntersection(const Plane &a, const Plane &b, Ray &r);
+
+    IntersectionClass rayPlaneIntersection(const Plane &p,
+                                           const Vector &v1,
+                                           const Vector &v2,
+                                           Vector &v,
+                                           double &t);
+
+    IntersectionClass lineSegmentPlaneIntersection(const Plane &p,
+                                                   const LineSegment &line,
+                                                   Vector &v);
+
+    RayIntersectionClass rayRayIntersection(const Ray &r1,
+                                            const Ray &r2,
+                                            Vector &v1,
+                                            Vector &v2,
+                                            double &mu1,
+                                            double &mu2);
+
+
+
+    // test whether point d is above, below or on the plane formed by the triangle a,b,c.
+    // return: +ve = d is below a,b,c
+    //         -ve = d is above a,b,c
+    //           0 = d is on a,b,c
+#if defined CARVE_USE_EXACT_PREDICATES
+    inline double orient3d(const Vector &a,
+                           const Vector &b,
+                           const Vector &c,
+                           const Vector &d) {
+      return shewchuk::orient3d(a.v, b.v, c.v, d.v);
+    }
+#else
+    inline double orient3d(const Vector &a,
+                           const Vector &b,
+                           const Vector &c,
+                           const Vector &d) {
+      return dotcross((a - d), (b - d), (c - d));
+    }
+#endif
+
+    // Volume of a tetrahedron described by 4 points. Will be
+    // positive if the anticlockwise normal of a,b,c is oriented out
+    // of the tetrahedron.
+    //
+    // see: http://mathworld.wolfram.com/Tetrahedron.html
+    inline double tetrahedronVolume(const Vector &a,
+                                    const Vector &b,
+                                    const Vector &c,
+                                    const Vector &d) {
+      return dotcross((a - d), (b - d), (c - d)) / 6.0;
+    }
+
+    /** 
+     * \brief Determine whether p is internal to the wedge defined by
+     *        the area between the planes defined by a,b,c and a,b,d
+     *        angle abc, where ab is the apex of the angle.
+     *
+     * @param[in] a 
+     * @param[in] b 
+     * @param[in] c
+     * @param[in] d
+     * @param[in] p 
+     * 
+     * @return true, if p is contained in the wedge defined by the
+     *               area between the planes defined by a,b,c and
+     *               a,b,d. If the wedge is reflex, p is considered to
+     *               be contained if it lies on either plane. Acute
+     *               wdges do not contain p if p lies on either
+     *               plane. This is so that internalToWedge(a,b,c,d,p) =
+     *               !internalToWedge(a,b,d,c,p)
+     */
+    inline bool internalToWedge(const Vector &a,
+                                const Vector &b,
+                                const Vector &c,
+                                const Vector &d,
+                                const Vector &p) {
+      bool reflex = (c < d) ?
+        orient3d(a, b, c, d) >= 0.0 :
+        orient3d(a, b, d, c) < 0.0;
+
+      double d1 = orient3d(a, b, c, p);
+      double d2 = orient3d(a, b, d, p);
+
+      if (reflex) {
+        // above a,b,c or below a,b,d (or coplanar with either)
+        return d1 <= 0.0 || d2 >= 0.0;
+      } else {
+        // above a,b,c and below a,b,d
+        return d1 < 0.0 && d2 > 0.0;
+      }
+    }
+
+    /** 
+     * \brief Determine the ordering relationship of a and b, when
+     *        rotating around direction, starting from base.
+     *
+     * @param[in] adirection
+     * @param[in] base
+     * @param[in] a
+     * @param[in] b
+     * 
+     * @return 
+     *         * -1, if a is ordered before b around, rotating about direction.
+     *         * 0, if a and b are equal in angle.
+     *         * +1, if a is ordered after b around, rotating about direction.
+     */
+    inline int compareAngles(const Vector &direction, const Vector &base, const Vector &a, const Vector &b) {
+      const double d1 = carve::geom3d::orient3d(carve::geom::VECTOR(0,0,0), direction, a, b);
+      const double d2 = carve::geom3d::orient3d(carve::geom::VECTOR(0,0,0), direction, base, a);
+      const double d3 = carve::geom3d::orient3d(carve::geom::VECTOR(0,0,0), direction, base, b);
+
+      // CASE: a and b are coplanar wrt. direction.
+      if (d1 == 0.0) {
+        // a and b point in the same direction.
+        if (dot(a, b) > 0.0) {
+          // Neither is less than the other.
+          return 0;
+        }
+
+        // a and b point in opposite directions.
+        // * if d2 < 0.0, a is above plane(direction, base) and is less
+        //   than b.
+        // * if d2 == 0.0 a is coplanar with plane(direction, base) and is
+        //   less than b if it points in the same direction as base.
+        // * if d2 > 0.0, a is below plane(direction, base) and is greater
+        //   than b.
+
+        if (d2 == 0.0) { return dot(a, base) > 0.0 ? -1 : +1; }
+        if (d3 == 0.0) { return dot(b, base) > 0.0 ? +1 : -1; }
+        if (d2 < 0.0 && d3 > 0.0) return -1;
+        if (d2 > 0.0 && d3 < 0.0) return +1;
+
+        // both a and b are to one side of plane(direction, base) -
+        // rounding error (if a and b are truly coplanar with
+        // direction, one should be above, and one should be below any
+        // other plane that is not itself coplanar with
+        // plane(direction, a|b) - which would imply d2 and d3 == 0.0).
+
+        // If both are below plane(direction, base) then the one that
+        // points in the same direction as base is greater.
+        // If both are above plane(direction, base) then the one that
+        // points in the same direction as base is lesser.
+        if (d2 > 0.0) { return dot(a, base) > 0.0 ? +1 : -1; }
+        else          { return dot(a, base) > 0.0 ? -1 : +1; }
+      }
+
+      // CASE: a and b are not coplanar wrt. direction
+
+      if (d2 < 0.0) {
+        // if a is above plane(direction,base), then a is less than b if
+        // b is below plane(direction,base) or b is above plane(direction,a)
+        return (d3 > 0.0 || d1 < 0.0) ? -1 : +1;
+      } else if (d2 == 0.0) {
+        // if a is on plane(direction,base) then a is less than b if a
+        // points in the same direction as base, or b is below
+        // plane(direction,base)
+        return (dot(a, base) > 0.0 || d3 > 0.0) ? -1 : +1;
+      } else {
+        // if a is below plane(direction,base), then a is less than b if b
+        // is below plane(direction,base) and b is above plane(direction,a)
+        return (d3 > 0.0 && d1 < 0.0) ? -1 : +1;
+      }
+    }
+
+    // The anticlockwise angle from vector "from" to vector "to", oriented around the vector "orient".
+    static inline double antiClockwiseAngle(const Vector &from, const Vector &to, const Vector &orient) {
+      double dp = dot(from, to);
+      Vector cp = cross(from, to);
+      if (cp.isZero()) {
+        if (dp < 0) {
+          return M_PI;
+        } else {
+          return 0.0;
+        }
+      } else {
+        if (dot(cp, orient) > 0.0) {
+          return acos(dp);
+        } else {
+          return M_TWOPI - acos(dp);
+        }
+      }
+    }
+
+
+
+    static inline double antiClockwiseOrdering(const Vector &from, const Vector &to, const Vector &orient) {
+      double dp = dot(from, to);
+      Vector cp = cross(from, to);
+      if (cp.isZero()) {
+        if (dp < 0) {
+          return 2.0;
+        } else {
+          return 0.0;
+        }
+      } else {
+        if (dot(cp, orient) > 0.0) {
+          // 1..-1 -> 0..2
+          return 1.0 - dp;
+        } else {
+          // -1..1 -> 2..4
+          return dp + 1.0;
+        }
+      }
+    }
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/geom_impl.hpp b/extern/carve/include/carve/geom_impl.hpp
new file mode 100644
index 00000000000..4463ba2bd88
--- /dev/null
+++ b/extern/carve/include/carve/geom_impl.hpp
@@ -0,0 +1,651 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/math.hpp>
+
+namespace carve {
+  namespace geom {
+
+
+
+    template<unsigned ndim>
+    double vector<ndim>::length2() const { return dot(*this, *this); }
+    template<unsigned ndim>
+    double vector<ndim>::length() const { return sqrt(dot(*this, *this)); }
+
+    template<unsigned ndim>
+    vector<ndim> &vector<ndim>::normalize() { *this /= length(); return *this; }
+    template<unsigned ndim>
+    vector<ndim> vector<ndim>::normalized() const { return *this / length(); }
+
+    template<unsigned ndim>
+    bool vector<ndim>::exactlyZero() const {
+      for (unsigned i = 0; i < ndim; ++i) if (this->v[i]) return false;
+      return true;
+    }
+    template<unsigned ndim>
+    bool vector<ndim>::isZero(double epsilon) const {
+      return length2() < epsilon * epsilon;
+    }
+
+    template<unsigned ndim>
+    void vector<ndim>::setZero() { for (size_t i = 0; i < ndim; ++i) this->v[i] = 0.0; }
+
+    template<unsigned ndim>
+    void vector<ndim>::fill(double val)  { for (size_t i = 0; i < ndim; ++i) this->v[i] = val; }
+
+    template<unsigned ndim>
+    vector<ndim> &vector<ndim>::scaleBy(double d) { for (unsigned i = 0; i < ndim; ++i) this->v[i] *= d; return *this; }
+    template<unsigned ndim>
+    vector<ndim> &vector<ndim>::invscaleBy(double d) { for (unsigned i = 0; i < ndim; ++i) this->v[i] /= d; return *this; }
+
+    template<unsigned ndim>
+    vector<ndim> vector<ndim>::scaled(double d) const { return *this * d; }
+    template<unsigned ndim>
+    vector<ndim> vector<ndim>::invscaled(double d) const { return *this / d; }
+
+    template<unsigned ndim>
+    vector<ndim> &vector<ndim>::negate() { for (unsigned i = 0; i < ndim; ++i) this->v[i] = -this->v[i]; return *this; }
+    template<unsigned ndim>
+    vector<ndim> vector<ndim>::negated() const { return -*this; }
+
+    template<unsigned ndim>
+    double &vector<ndim>::operator[](unsigned i) { return this->v[i]; }
+    template<unsigned ndim>
+    const double &vector<ndim>::operator[](unsigned i) const { return this->v[i]; }
+
+    template<unsigned ndim>
+    template<typename assign_t>
+    vector<ndim> &vector<ndim>::operator=(const assign_t &t) {
+      for (unsigned i = 0; i < ndim; ++i) this->v[i] = t[i];
+      return *this;
+    }
+
+    template<unsigned ndim>
+    std::string vector<ndim>::asStr() const {
+      std::ostringstream out;
+      out << '<';
+      out << std::setprecision(24);
+      for (unsigned i = 0; i < ndim; ++i) { if (i) out << ','; out << this->v[i]; }
+      out << '>';
+      return out.str();
+    }
+
+
+
+    template<unsigned ndim>
+    vector<ndim> operator+(const vector<ndim> &a, const vector<ndim> &b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] + b[i];
+      return c;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> operator+(const vector<ndim> &a, double b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] + b;
+      return c;
+    }
+
+    template<unsigned ndim, typename val_t>
+    vector<ndim> operator+(const vector<ndim> &a, const val_t &b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] + b[i];
+      return c;
+    }
+
+    template<unsigned ndim, typename val_t>
+    vector<ndim> operator+(const val_t &a, const vector<ndim> &b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] + b[i];
+      return c;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> &operator+=(vector<ndim> &a, const vector<ndim> &b) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] += b[i];
+      return a;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> &operator+=(vector<ndim> &a, double b) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] += b;
+      return a;
+    }
+
+    template<unsigned ndim, typename val_t>
+    vector<ndim> &operator+=(vector<ndim> &a, const val_t &b) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] += b[i];
+      return a;
+    }
+
+
+
+    template<unsigned ndim>
+    vector<ndim> operator-(const vector<ndim> &a) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = -a[i];
+      return c;
+    }
+
+
+
+    template<unsigned ndim>
+    vector<ndim> operator-(const vector<ndim> &a, double b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] - b;
+      return c;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> operator-(const vector<ndim> &a, const vector<ndim> &b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] - b[i];
+      return c;
+    }
+
+    template<unsigned ndim, typename val_t>
+    vector<ndim> operator-(const vector<ndim> &a, const val_t &b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] - b[i];
+      return c;
+    }
+
+    template<unsigned ndim, typename val_t>
+    vector<ndim> operator-(const val_t &a, const vector<ndim> &b) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] - b[i];
+      return c;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> &operator-=(vector<ndim> &a, const vector<ndim> &b) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] -= b[i];
+      return a;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> &operator-=(vector<ndim> &a, double b) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] -= b;
+      return a;
+    }
+
+    template<unsigned ndim, typename val_t>
+    vector<ndim> &operator-=(vector<ndim> &a, const val_t &b) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] -= b[i];
+      return a;
+    }
+
+
+
+    template<unsigned ndim>
+    vector<ndim> operator*(const vector<ndim> &a, double s) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] * s;
+      return c;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> operator*(double s, const vector<ndim> &a) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] * s;
+      return c;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> &operator*=(vector<ndim> &a, double s) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] *= s;
+      return a;
+    }
+
+
+
+    template<unsigned ndim>
+    vector<ndim> operator/(const vector<ndim> &a, double s) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = a[i] / s;
+      return c;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> &operator/=(vector<ndim> &a, double s) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] /= s;
+      return a;
+    }
+
+
+
+    template<unsigned ndim>
+    bool operator==(const vector<ndim> &a, const vector<ndim> &b) {
+      for (unsigned i = 0; i < ndim; ++i) { if (a[i] != b[i]) return false; }
+      return true;
+    }
+
+    template<unsigned ndim>
+    bool operator!=(const vector<ndim> &a, const vector<ndim> &b) {
+      return !(a == b);
+    }
+
+    template<unsigned ndim>
+    bool operator<(const vector<ndim> &a, const vector<ndim> &b) {
+      for (unsigned i = 0; i < ndim; ++i) { if (a[i] < b[i]) return true; if (a[i] > b[i]) return false; }
+      return false;
+    }
+
+    template<unsigned ndim>
+    bool operator<=(const vector<ndim> &a, const vector<ndim> &b) {
+      return !(b < a);
+    }
+
+    template<unsigned ndim>
+    bool operator>(const vector<ndim> &a, const vector<ndim> &b) {
+      return b < a;
+    }
+
+    template<unsigned ndim>
+    bool operator>=(const vector<ndim> &a, const vector<ndim> &b) {
+      return !(a < b);
+    }
+
+
+
+    template<unsigned ndim>
+    vector<ndim> abs(const vector<ndim> &a) {
+      vector<ndim> c(NOINIT);
+      for (unsigned i = 0; i < ndim; ++i) c[i] = fabs(a[i]);
+      return c;
+    }
+
+    template<unsigned ndim>
+    double distance2(const vector<ndim> &a, const vector<ndim> &b) {
+      return (b - a).length2();
+    }
+
+    template<unsigned ndim>
+    double distance(const vector<ndim> &a, const vector<ndim> &b) {
+      return (b - a).length();
+    }
+
+    template<unsigned ndim>
+    bool equal(const vector<ndim> &a, const vector<ndim> &b) {
+      return (b - a).isZero();
+    }
+
+    template<unsigned ndim>
+    int smallestAxis(const vector<ndim> &a) {
+      int x = 0;
+      double y = fabs(a[0]);
+      for (unsigned i = 1; i < ndim; ++i) {
+        double z = fabs(a[i]);
+        if (z <= y) { y = z; x = i; }
+      }
+      return x;
+    }
+
+    template<unsigned ndim>
+    int largestAxis(const vector<ndim> &a) {
+      int x = 0;
+      double y = fabs(a[0]);
+      for (unsigned i = 1; i < ndim; ++i) {
+        double z = fabs(a[i]);
+        if (z > y) { y = z; x = i; }
+      }
+      return x;
+    }
+
+    template<unsigned ndim>
+    vector<2> select(const vector<ndim> &a, int a1, int a2) {
+      vector<2> r(NOINIT);
+      r.v[0] = a.v[a1]; r.v[1] = a.v[a2];
+      return r;
+    }
+
+    template<unsigned ndim>
+    vector<3> select(const vector<ndim> &a, int a1, int a2, int a3) {
+      vector<3> r(NOINIT);
+      r.v[0] = a.v[a1]; r.v[1] = a.v[a2]; r.v[2] = a.v[a3];
+      return r;
+    }
+
+    template<unsigned ndim, typename assign_t, typename oper_t>
+    vector<ndim> &assign_op(vector<ndim> &a, const assign_t &t, oper_t op) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] = op(t[i]);
+      return a;
+    }
+
+    template<unsigned ndim, typename assign1_t, typename assign2_t, typename oper_t>
+    vector<ndim> &assign_op(vector<ndim> &a, const assign1_t &t1, const assign2_t &t2, oper_t op) {
+      for (unsigned i = 0; i < ndim; ++i) a[i] = op(t1[i], t2[i]);
+      return a;
+    }
+
+    template<unsigned ndim, typename iter_t>
+    void bounds(iter_t begin, iter_t end, vector<ndim> &min, vector<ndim> &max) {
+      if (begin == end) {
+        min.setZero();
+        max.setZero();
+      } else {
+        min = max = *begin;
+        while (++begin != end) {
+          vector<ndim> v = *begin;
+          assign_op(min, min, v, carve::util::min_functor());
+          assign_op(max, max, v, carve::util::max_functor());
+        }
+      }
+    }
+
+    template<unsigned ndim, typename iter_t, typename adapt_t>
+    void bounds(iter_t begin, iter_t end, adapt_t adapt, vector<ndim> &min, vector<ndim> &max) {
+      if (begin == end) {
+        min.setZero();
+        max.setZero();
+      } else {
+        min = max = adapt(*begin);
+        while (++begin != end) {
+          vector<ndim> v = adapt(*begin);
+          assign_op(min, min, v, carve::util::min_functor());
+          assign_op(max, max, v, carve::util::max_functor());
+        }
+      }
+    }
+
+    template<unsigned ndim, typename iter_t, typename adapt_t>
+    void centroid(iter_t begin, iter_t end, adapt_t adapt, vector<ndim> &c) {
+      c.setZero();
+      int n = 0;
+      while (begin != end) { c += adapt(*begin++); ++n; }
+      c /= double(n);
+    }
+
+    template<unsigned ndim, typename val_t>
+    double dot(const vector<ndim> &a, const val_t &b) {
+      double r = 0.0;
+      for (unsigned i = 0; i < ndim; ++i) r += a[i] * b[i];
+      return r;
+    }
+
+    static inline vector<3> cross(const vector<3> &a, const vector<3> &b) {
+      // Compute a x b
+      return VECTOR(+(a.y * b.z - a.z * b.y),
+                    -(a.x * b.z - a.z * b.x),
+                    +(a.x * b.y - a.y * b.x));
+    }
+
+    static inline double cross(const vector<2> &a, const vector<2> &b) {
+      // Compute a x b
+      return a.x * b.y - b.x * a.y;
+    }
+
+    static inline double dotcross(const vector<3> &a, const vector<3> &b, const vector<3> &c) {
+      // Compute a . (b x c)
+      return
+        (a.x * b.y * c.z + a.y * b.z * c.x + a.z * b.x * c.y) -
+        (a.x * b.z * c.y + a.y * b.x * c.z + a.z * b.y * c.x);
+    }
+
+
+
+    template<unsigned ndim>
+    double distance(const axis_pos &a, const vector<ndim> &b) {
+      return fabs(b[a.axis] - a.pos);
+    }
+
+    template<unsigned ndim>
+    double distance2(const axis_pos &a, const vector<ndim> &b) {
+      double r = fabs(b[a.axis] - a.pos);
+      return r * r;
+    }
+
+    template<unsigned ndim> bool operator<(const axis_pos &a, const vector<ndim> &b) { return a.pos < b[a.axis]; }
+    template<unsigned ndim> bool operator<(const vector<ndim> &a, const axis_pos &b) { return a[b.axis] < b.pos; }
+
+    template<unsigned ndim> bool operator<=(const axis_pos &a, const vector<ndim> &b) { return a.pos <= b[a.axis]; }
+    template<unsigned ndim> bool operator<=(const vector<ndim> &a, const axis_pos &b) { return a[b.axis] <= b.pos; }
+
+    template<unsigned ndim> bool operator>(const axis_pos &a, const vector<ndim> &b) { return a.pos > b[a.axis]; }
+    template<unsigned ndim> bool operator>(const vector<ndim> &a, const axis_pos &b) { return a[b.axis] > b.pos; }
+
+    template<unsigned ndim> bool operator>=(const axis_pos &a, const vector<ndim> &b) { return a.pos >= b[a.axis]; }
+    template<unsigned ndim> bool operator>=(const vector<ndim> &a, const axis_pos &b) { return a[b.axis] >= b.pos; }
+
+    template<unsigned ndim> bool operator==(const axis_pos &a, const vector<ndim> &b) { return a.pos == b[a.axis]; }
+    template<unsigned ndim> bool operator==(const vector<ndim> &a, const axis_pos &b) { return a[b.axis] == b.pos; }
+
+    template<unsigned ndim> bool operator!=(const axis_pos &a, const vector<ndim> &b) { return a.pos != b[a.axis]; }
+    template<unsigned ndim> bool operator!=(const vector<ndim> &a, const axis_pos &b) { return a[b.axis] != b.pos; }
+
+
+
+    template<unsigned ndim>
+    bool ray<ndim>::OK() const {
+      return !D.isZero();
+    }
+
+    template<unsigned ndim>
+    ray<ndim> rayThrough(const vector<ndim> &a, const vector<ndim> &b) {
+      return ray<ndim>(b - a, a);
+    }
+
+    static inline double distance2(const ray<3> &r, const vector<3> &v) {
+      return cross(r.D, v - r.v).length2() / r.D.length2();
+    }
+
+    static inline double distance(const ray<3> &r, const vector<3> &v) {
+      return sqrt(distance2(r, v));
+    }
+
+    static inline double distance2(const ray<2> &r, const vector<2> &v) {
+      double t = cross(r.D, v - r.v);
+      return (t * t) / r.D.length2();
+    }
+
+    static inline double distance(const ray<2> &r, const vector<2> &v) {
+      return sqrt(distance2(r, v));
+    }
+
+
+    
+    template<unsigned ndim>
+    void linesegment<ndim>::update() {
+      midpoint = (v2 + v1) / 2.0;
+      half_length = (v2 - v1) / 2.0;
+    }
+
+    template<unsigned ndim>
+    bool linesegment<ndim>::OK() const {
+      return !half_length.isZero();
+    }
+
+    template<unsigned ndim>
+    void linesegment<ndim>::flip() {
+      std::swap(v1, v2);
+      half_length = (v2 - v1) / 2.0;
+    }
+
+    template<unsigned ndim>
+    aabb<ndim> linesegment<ndim>::getAABB() const {
+      aabb<ndim> r;
+      r.fit(v1, v2);
+      return r;
+    }
+
+    template<unsigned ndim>
+    linesegment<ndim>::linesegment(const vector_t &_v1, const vector_t &_v2) : v1(_v1), v2(_v2) {
+      update();
+    }
+
+
+
+    template<unsigned ndim>
+    double distance2(const linesegment<ndim> &l, const vector<ndim> &v) {
+      vector<ndim> D = l.v2 - l.v1;
+      double t = dot(v - l.v1, D) / dot(D, D);
+      if (t <= 0.0) return (v - l.v1).length2();
+      if (t >= 1.0) return (v - l.v2).length2();
+      vector<ndim> vc = D * t + l.v1;
+      return (v - vc).length2();
+    }
+
+    template<unsigned ndim>
+    double distance(const linesegment<ndim> &l, const vector<ndim> &v) {
+      return sqrt(distance2(l, v));
+    }
+
+
+    template<unsigned ndim>
+    void plane<ndim>::negate() {
+      N.negate();
+      d = -d;
+    }
+
+    template<unsigned ndim>
+    plane<ndim>::plane() {
+      N.setZero();
+      N[0] = 1.0;
+      d= 0.0;
+    }
+
+    template<unsigned ndim>
+    plane<ndim>::plane(const vector_t &_N, vector_t _p) : N(_N), d(-dot(_p, _N)) {
+    }
+
+    template<unsigned ndim>
+    plane<ndim>::plane(const vector_t &_N, double _d) : N(_N), d(_d) {
+    }
+
+
+
+    template<unsigned ndim>
+    plane<ndim> operator-(const plane<ndim> &p) {
+      return plane<ndim>(-p.N, -p.d);
+    }
+
+    template<unsigned ndim, typename val_t>
+    double distance(const plane<ndim> &plane, const val_t &point) {
+      return dot(plane.N, point) + plane.d;
+    }
+
+    template<unsigned ndim, typename val_t>
+    double distance2(const plane<ndim> &plane, const val_t &point) {
+      double d = distance(plane, point);
+      return d * d;
+    }
+
+    template<unsigned ndim>
+    vector<ndim> closestPoint(const plane<ndim> &p, const vector<ndim> &v) {
+      return v - p.N * (p.d + dot(p.N, v)) / dot(p.N, p.N);
+    }
+
+
+
+    template<unsigned ndim>
+    aabb<ndim> sphere<ndim>::getAABB() const {
+      aabb<ndim> r;
+      r.fit(C - r, C + r);
+    }
+
+    template<unsigned ndim>
+    sphere<ndim>::sphere() {
+      C.setZero();
+      r = 1.0;
+    }
+
+    template<unsigned ndim>
+    sphere<ndim>::sphere(const vector_t &_C, double _r) : C(_C), r(_r) {
+    }
+
+
+
+    template<unsigned ndim, typename val_t>
+    double distance(const sphere<ndim> &sphere, const val_t &point) {
+      return std::max(0.0, distance(sphere.C, point) - sphere.r);
+    }
+
+    template<unsigned ndim, typename val_t>
+    double distance2(const sphere<ndim> &sphere, const val_t &point) {
+      return std::max(0.0, distance2(sphere.C, point) - sphere.r * sphere.r);
+    }
+
+    template<unsigned ndim>
+    vector<ndim> closestPoint(const sphere<ndim> &sphere, const vector<ndim> &point) {
+      return (point - sphere.C).normalized() * sphere.r;
+    }
+
+
+
+    template<unsigned ndim>
+    aabb<ndim> tri<ndim>::getAABB() const {
+      aabb<ndim> aabb;
+      aabb.fit(v[0], v[1], v[2]);
+      return aabb;
+    }
+
+    template<unsigned ndim>
+    tri<ndim>::tri(vector_t _v[3]) {
+      std::copy(v, v+3, _v);
+    }
+
+    template<unsigned ndim>
+    tri<ndim>::tri(const vector_t &a, const vector_t &b, const vector_t &c) {
+      v[0] = a;
+      v[1] = b;
+      v[2] = c;
+    }
+
+
+
+    template<unsigned ndim>
+    std::ostream &operator<<(std::ostream &o, const vector<ndim> &v) {
+      o << v.asStr();
+      return o;
+    }
+
+    template<unsigned ndim>
+    std::ostream &operator<<(std::ostream &o, const carve::geom::plane<ndim> &p) {
+      o << p.N << ";" << p.d;
+      return o;
+    }
+    
+    template<unsigned ndim>
+    std::ostream &operator<<(std::ostream &o, const carve::geom::sphere<ndim> &sphere) {
+      o << "{sphere " << sphere.C << ";" << sphere.r << "}";
+      return o;
+    }
+    
+    template<unsigned ndim>
+    std::ostream &operator<<(std::ostream &o, const carve::geom::tri<ndim> &tri) {
+      o << "{tri " << tri.v[0] << ";" << tri.v[1] << ";" << tri.v[2] << "}";
+      return o;
+    }
+
+
+
+    template<unsigned ndim>
+    double distance(const tri<ndim> &tri, const vector<ndim> &pt) {
+      return distance(closestPoint(tri, pt), pt);
+    }
+
+
+
+    template<unsigned ndim>
+    double distance2(const tri<ndim> &tri, const vector<ndim> &pt) {
+      return distance2(closestPoint(tri, pt), pt);
+    }
+  }
+}
diff --git a/extern/carve/include/carve/gnu_cxx.h b/extern/carve/include/carve/gnu_cxx.h
new file mode 100644
index 00000000000..280fa360478
--- /dev/null
+++ b/extern/carve/include/carve/gnu_cxx.h
@@ -0,0 +1,4 @@
+// Copyright 2006 Tobias Sargeant (toby@permuted.net)
+// All rights reserved.
+
+#pragma once
diff --git a/extern/carve/include/carve/heap.hpp b/extern/carve/include/carve/heap.hpp
new file mode 100644
index 00000000000..20bdcf003e5
--- /dev/null
+++ b/extern/carve/include/carve/heap.hpp
@@ -0,0 +1,425 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+namespace carve {
+  namespace heap {
+    namespace detail {
+
+
+
+      struct ignore_position_t {
+        template<typename value_t>
+        void operator()(value_t &val, size_t idx) const {}
+      };
+
+
+
+      template<typename random_access_iter_t,
+               typename distance_t,
+               typename value_t,
+               typename pred_t,
+               typename pos_notifier_t>
+      void _adjust_heap(random_access_iter_t begin,
+                        distance_t pos,
+                        distance_t len,
+                        value_t val,
+                        pred_t pred,
+                        pos_notifier_t notify) {
+        const distance_t top = pos;
+
+        distance_t child = pos * 2 + 2;
+        while (child < len) {
+          if (pred(begin[child], begin[child - 1])) child--;
+
+          begin[pos] = begin[child];
+          notify(begin[pos], pos);
+          pos = child;
+          child = pos * 2 + 2;
+        }
+
+        if (child == len) {
+          child--;
+          begin[pos] = begin[child];
+          notify(begin[pos], pos);
+          pos = child;
+        }
+
+        distance_t parent = (pos - 1) / 2;
+        while (pos > top && pred(begin[parent], val)) {
+          begin[pos] = begin[parent];
+          notify(begin[pos], pos);
+          pos = parent;
+          parent = (pos - 1) / 2;
+        }
+
+        begin[pos] = val;
+        notify(begin[pos], pos);
+      }
+
+
+
+      template<typename random_access_iter_t,
+               typename distance_t,
+               typename value_t,
+               typename pred_t,
+               typename pos_notifier_t>
+      void _push_heap(random_access_iter_t begin,
+                      distance_t pos,
+                      value_t val,
+                      pred_t pred,
+                      pos_notifier_t notify) {
+        distance_t parent = (pos - 1) / 2;
+        while (pos > 0 && pred(begin[parent], val)) {
+          begin[pos] = begin[parent];
+          notify(begin[pos], pos);
+          pos = parent;
+          parent = (pos - 1) / 2;
+        }
+        begin[pos] = val;
+        notify(begin[pos], pos);
+      }
+
+
+
+      template<typename random_access_iter_t,
+               typename distance_t,
+               typename pred_t,
+               typename pos_notifier_t>
+      void _remove_heap(random_access_iter_t begin,
+                        distance_t pos,
+                        distance_t len,
+                        pred_t pred,
+                        pos_notifier_t notify) {
+        --len;
+        if (pos != len) {
+          typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+          value_t removed = begin[pos];
+          _adjust_heap(begin, pos, len, begin[len], pred, notify);
+          begin[len] = removed;
+          notify(begin[len], len);
+        }
+      }
+
+
+
+      template<typename random_access_iter_t,
+               typename distance_t,
+               typename pred_t,
+               typename pos_notifier_t>
+      void _make_heap(random_access_iter_t begin,
+                      distance_t len,
+                      pred_t pred,
+                      pos_notifier_t notify) {
+        for (distance_t pos = len / 2; pos > 0; ) {
+          --pos;
+          _adjust_heap(begin, pos, len, begin[pos], pred, ignore_position_t());
+        }
+        for (distance_t pos = 0; pos < len; ++pos) {
+          notify(begin[pos], pos);
+        }
+      }
+
+
+
+      template<typename random_access_iter_t,
+               typename distance_t,
+               typename pred_t>
+      void _make_heap(random_access_iter_t begin,
+                      distance_t len,
+                      pred_t pred,
+                      ignore_position_t) {
+        for (distance_t pos = len / 2; pos > 0; ) {
+          --pos;
+          _adjust_heap(begin, pos, len, begin[pos], pred, ignore_position_t());
+        }
+      }
+
+
+
+      template<typename random_access_iter_t,
+               typename distance_t,
+               typename pred_t>
+      bool _is_heap(random_access_iter_t begin,
+                    distance_t len,
+                    pred_t pred) {
+        distance_t parent = 0;
+
+        for (distance_t child = 1; child < len; ++child) {
+          if (pred(begin[parent], begin[child])) {
+            return false;
+          }
+          if (++child == len) break;
+          if (pred(begin[parent], begin[child])) {
+          return false;
+          }
+          ++parent;
+        }
+
+        return true;
+      }
+
+
+
+    }
+
+
+
+    template<typename random_access_iter_t>
+    void adjust_heap(random_access_iter_t begin,
+                     random_access_iter_t end,
+                     random_access_iter_t pos) {
+      typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+
+      detail::_adjust_heap(begin, pos - begin, end - begin, *pos, std::less<value_t>());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t>
+    void adjust_heap(random_access_iter_t begin,
+                     random_access_iter_t end,
+                     random_access_iter_t pos,
+                     pred_t pred) {
+      detail::_adjust_heap(begin, pos - begin, end - begin, *pos, pred);
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t,
+             typename pos_notifier_t>
+    void adjust_heap(random_access_iter_t begin,
+                     random_access_iter_t end,
+                     random_access_iter_t pos,
+                     pred_t pred,
+                     pos_notifier_t notify) {
+      detail::_adjust_heap(begin, pos - begin, end - begin, *pos, pred, notify);
+    }
+
+
+
+    template<typename random_access_iter_t>
+    void remove_heap(random_access_iter_t begin,
+                     random_access_iter_t end,
+                     random_access_iter_t pos) {
+      typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+
+      detail::_remove_heap(begin, pos - begin, end - begin, std::less<value_t>(), detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t>
+    void remove_heap(random_access_iter_t begin,
+                     random_access_iter_t end,
+                     random_access_iter_t pos,
+                     pred_t pred) {
+      detail::_remove_heap(begin, pos - begin, end - begin, pred, detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t,
+             typename pos_notifier_t>
+    void remove_heap(random_access_iter_t begin,
+                     random_access_iter_t end,
+                     random_access_iter_t pos,
+                     pred_t pred,
+                     pos_notifier_t notify) {
+      detail::_remove_heap(begin, pos - begin, end - begin, pred, notify);
+    }
+
+
+
+    template<typename random_access_iter_t>
+    void pop_heap(random_access_iter_t begin,
+                  random_access_iter_t end) {
+      typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      detail::_remove_heap(begin, distance_t(0), end - begin, std::less<value_t>(), detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t>
+    void pop_heap(random_access_iter_t begin,
+                  random_access_iter_t end,
+                  pred_t pred) {
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      detail::_remove_heap(begin, distance_t(0), end - begin, pred, detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t,
+             typename pos_notifier_t>
+    void pop_heap(random_access_iter_t begin,
+                     random_access_iter_t end,
+                     pred_t pred,
+                     pos_notifier_t notify) {
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      detail::_remove_heap(begin, distance_t(0), end - begin, pred, notify);
+    }
+
+
+
+    template<typename random_access_iter_t>
+    void push_heap(random_access_iter_t begin,
+                   random_access_iter_t end) {
+      typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      distance_t pos = end - begin - 1;
+      detail::_push_heap(begin, pos, begin[pos], std::less<value_t>(), detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t>
+    void push_heap(random_access_iter_t begin,
+                   random_access_iter_t end,
+                   pred_t pred) {
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      distance_t pos = end - begin - 1;
+      detail::_push_heap(begin, pos, begin[pos], pred, detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t,
+             typename pos_notifier_t>
+    void push_heap(random_access_iter_t begin,
+                   random_access_iter_t end,
+                   pred_t pred,
+                   pos_notifier_t notify) {
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      distance_t pos = end - begin - 1;
+      detail::_push_heap(begin, pos, begin[pos], pred, notify);
+    }
+
+
+
+    template<typename random_access_iter_t>
+    void make_heap(random_access_iter_t begin,
+                   random_access_iter_t end) {
+      typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+
+      detail::_make_heap(begin, end - begin, std::less<value_t>(), detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t>
+    void make_heap(random_access_iter_t begin,
+                   random_access_iter_t end,
+                   pred_t pred) {
+      detail::_make_heap(begin, end - begin, pred, detail::ignore_position_t());
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t,
+             typename pos_notifier_t>
+    void make_heap(random_access_iter_t begin,
+                   random_access_iter_t end,
+                   pred_t pred,
+                   pos_notifier_t notify) {
+      detail::_make_heap(begin, end - begin, pred, notify);
+    }
+
+
+
+    template<typename random_access_iter_t>
+    bool is_heap(random_access_iter_t begin,
+                 random_access_iter_t end) {
+      typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+
+      return detail::_is_heap(begin, end - begin, std::less<value_t>());
+    }
+
+
+
+    template<typename random_access_iter_t, typename pred_t>
+    bool is_heap(random_access_iter_t begin,
+                 random_access_iter_t end,
+                 pred_t pred) {
+      return detail::_is_heap(begin, end - begin, pred);
+    }
+
+
+
+    template<typename random_access_iter_t>
+    void sort_heap(random_access_iter_t begin,
+                   random_access_iter_t end) {
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+      typedef typename std::iterator_traits<random_access_iter_t>::value_type value_t;
+
+      for (distance_t len = end - begin; len > 1; --len) {
+        detail::_remove_heap(begin, distance_t(0), len, std::less<value_t>(), detail::ignore_position_t());
+      }
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t>
+    void sort_heap(random_access_iter_t begin,
+                   random_access_iter_t end,
+                   pred_t pred) {
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      for (distance_t len = end - begin; len > 1; --len) {
+        detail::_remove_heap(begin, distance_t(0), len, pred, detail::ignore_position_t());
+      }
+    }
+
+
+
+    template<typename random_access_iter_t,
+             typename pred_t,
+             typename pos_notifier_t>
+    void sort_heap(random_access_iter_t begin,
+                   random_access_iter_t end,
+                   pred_t pred,
+                   pos_notifier_t notify) {
+      typedef typename std::iterator_traits<random_access_iter_t>::difference_type distance_t;
+
+      for (distance_t len = end - begin; len > 1; --len) {
+        detail::_remove_heap(begin, distance_t(0), len, pred, detail::ignore_position_t());
+        notify(begin[len], len);
+      }
+      notify(begin[0], 0);
+    }
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/input.hpp b/extern/carve/include/carve/input.hpp
new file mode 100644
index 00000000000..a8bc8137d6c
--- /dev/null
+++ b/extern/carve/include/carve/input.hpp
@@ -0,0 +1,251 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/poly.hpp>
+#include <carve/mesh.hpp>
+#include <carve/polyline.hpp>
+#include <carve/pointset.hpp>
+
+
+
+namespace carve {
+  namespace input {
+
+    struct Data {
+      Data() {
+      }
+
+      virtual ~Data() {
+      }
+
+      virtual void transform(const carve::math::Matrix & /* transform */) {
+      }
+    };
+
+
+
+    struct VertexData : public Data {
+      std::vector<carve::geom3d::Vector> points;
+
+      VertexData() : Data() {
+      }
+
+      virtual ~VertexData() {
+      }
+
+      virtual void transform(const carve::math::Matrix &transform) {
+        for (size_t i = 0; i < points.size(); ++i) {
+          points[i] *= transform;
+        }
+      }
+
+      size_t addVertex(carve::geom3d::Vector point) {
+        size_t index = points.size();
+        points.push_back(point);
+        return index;
+      }
+  
+      inline void reserveVertices(int count) {
+        points.reserve(count);
+      }
+
+      size_t getVertexCount() const {
+        return points.size();
+      }
+
+      const carve::geom3d::Vector &getVertex(int index) const {
+        return points[index];
+      }
+    };
+
+
+
+    struct PolyhedronData : public VertexData {
+      std::vector<int> faceIndices;
+      int faceCount;
+
+      PolyhedronData() : VertexData(), faceIndices(), faceCount(0) {
+      }
+
+      virtual ~PolyhedronData() {
+      }
+
+      void reserveFaces(int count, int avgFaceSize) {
+        faceIndices.reserve(faceIndices.size() + count * (1 + avgFaceSize));
+      }
+  
+      int getFaceCount() const {
+        return faceCount;
+      }
+  
+      template <typename Iter>
+      void addFace(Iter begin, Iter end) {
+        size_t n = std::distance(begin, end);
+        faceIndices.reserve(faceIndices.size() + n + 1);
+        faceIndices.push_back(n);
+        std::copy(begin, end, std::back_inserter(faceIndices));
+        ++faceCount;
+      }
+  
+      void addFace(int a, int b, int c) {
+        faceIndices.push_back(3);
+        faceIndices.push_back(a);
+        faceIndices.push_back(b);
+        faceIndices.push_back(c);
+        ++faceCount;
+      }
+
+      void addFace(int a, int b, int c, int d) {
+        faceIndices.push_back(4);
+        faceIndices.push_back(a);
+        faceIndices.push_back(b);
+        faceIndices.push_back(c);
+        faceIndices.push_back(d);
+        ++faceCount;
+      }
+
+      void clearFaces() {
+        faceIndices.clear();
+        faceCount = 0;
+      }
+
+      carve::poly::Polyhedron *create() const {
+        return new carve::poly::Polyhedron(points, faceCount, faceIndices);
+      }
+
+      carve::mesh::MeshSet<3> *createMesh() const {
+        return new carve::mesh::MeshSet<3>(points, faceCount, faceIndices);
+      }
+    };
+
+
+
+    struct PolylineSetData : public VertexData {
+      typedef std::pair<bool, std::vector<int> > polyline_data_t;
+      std::list<polyline_data_t> polylines;
+
+      PolylineSetData() : VertexData(), polylines() {
+      }
+
+      virtual ~PolylineSetData() {
+      }
+
+      void beginPolyline(bool closed = false) {
+        polylines.push_back(std::make_pair(closed, std::vector<int>()));
+      }
+
+      void reservePolyline(size_t len) {
+        polylines.back().second.reserve(len);
+      }
+
+      void addPolylineIndex(int idx) {
+        polylines.back().second.push_back(idx);
+      }
+
+      carve::line::PolylineSet *create() const {
+        carve::line::PolylineSet *p = new carve::line::PolylineSet(points);
+
+        for (std::list<polyline_data_t>::const_iterator i = polylines.begin();
+             i != polylines.end();
+             ++i) {
+          p->addPolyline((*i).first, (*i).second.begin(), (*i).second.end());
+        }
+        return p;
+      }
+    };
+
+
+
+    struct PointSetData : public VertexData {
+
+      PointSetData() : VertexData() {
+      }
+
+      virtual ~PointSetData() {
+      }
+
+      carve::point::PointSet *create() const {
+        carve::point::PointSet *p = new carve::point::PointSet(points);
+        return p;
+      }
+    };
+
+
+
+    class Input {
+    public:
+      std::list<Data *> input;
+
+      Input() {
+      }
+
+      ~Input() {
+        for (std::list<Data *>::iterator i = input.begin(); i != input.end(); ++i) {
+          delete (*i);
+        }
+      }
+
+      void addDataBlock(Data *data) {
+        input.push_back(data);
+      }
+
+      void transform(const carve::math::Matrix &transform) {
+        if (transform == carve::math::Matrix::IDENT()) return;
+        for (std::list<Data *>::iterator i = input.begin(); i != input.end(); ++i) {
+          (*i)->transform(transform);
+        }
+      }
+
+      template<typename T>
+      static inline T *create(Data *d) {
+        return NULL;
+      }
+    };
+
+    template<>
+    inline carve::mesh::MeshSet<3> *Input::create(Data *d) {
+      PolyhedronData *p = dynamic_cast<PolyhedronData *>(d);
+      if (p == NULL) return NULL;
+      return p->createMesh();
+    }
+
+    template<>
+    inline carve::poly::Polyhedron *Input::create(Data *d) {
+      PolyhedronData *p = dynamic_cast<PolyhedronData *>(d);
+      if (p == NULL) return NULL;
+      return p->create();
+    }
+
+    template<>
+    inline carve::line::PolylineSet *Input::create(Data *d) {
+      PolylineSetData *p = dynamic_cast<PolylineSetData *>(d);
+      if (p == NULL) return NULL;
+      return p->create();
+    }
+
+    template<>
+    inline carve::point::PointSet *Input::create(Data *d) {
+      PointSetData *p = dynamic_cast<PointSetData *>(d);
+      if (p == NULL) return NULL;
+      return p->create();
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/interpolator.hpp b/extern/carve/include/carve/interpolator.hpp
new file mode 100644
index 00000000000..e1555105435
--- /dev/null
+++ b/extern/carve/include/carve/interpolator.hpp
@@ -0,0 +1,332 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/geom2d.hpp>
+#include <carve/poly.hpp>
+#include <carve/mesh.hpp>
+#include <carve/csg.hpp>
+
+namespace carve {
+  namespace interpolate {
+
+    static inline std::vector<double> polyInterpolate(const std::vector<carve::geom2d::P2> &s,
+                                                      const carve::geom2d::P2 &v) {
+      // see hormann et al. 2006
+      const size_t SZ = s.size();
+      std::vector<double> r;
+      std::vector<double> A;
+      std::vector<double> D;
+
+      std::vector<double> result;
+
+      r.resize(SZ);
+      A.resize(SZ);
+      D.resize(SZ);
+
+      result.resize(SZ, 0.0);
+
+      for (size_t i = 0; i < SZ; ++i) {
+        size_t i2 = (i + 1) % SZ;
+        carve::geom2d::P2 si = s[i] - v;
+        carve::geom2d::P2 si2 = s[i2] - v;
+
+        r[i] = sqrt(dot(si, si));
+        A[i] = cross(si, si2) / 2.0;
+        D[i] = dot(si, si2);
+        if (fabs(r[i]) < 1e-16) {
+          result[i] = 1.0;
+          return result;
+        } else if (fabs(A[i]) < 1e-16 && D[i] < 0.0) {
+          double r2 = sqrt(dot(si2, si2));
+          result[i2] = r[i] / (r[i] + r2);
+          result[i] = r2 / (r[i] + r2);
+          return result;
+        }
+      }
+
+      double w_sum = 0.0;
+
+      for (size_t i = 0; i < SZ; ++i) {
+        size_t i_m = (i + SZ - 1) % SZ;
+        size_t i_p = (i + 1) % SZ;
+
+        double w = 0.0;
+        if (fabs(A[i_m]) > 1e-16)
+          w += (r[i_m] - D[i_m] / r[i]) / A[i_m];
+        if (fabs(A[i]) > 1e-16)
+          w += (r[i_p] - D[i] / r[i]) / A[i];
+
+        result[i] = w;
+        w_sum += w;
+      }
+  
+      for (size_t i = 0; i < SZ; ++i) {
+        result[i] /= w_sum;
+      }
+
+//       carve::geom2d::P2 test;
+//       for (size_t i = 0; i < SZ; ++i) {
+//         test = test + result[i] * s[i];
+//       }
+
+      return result;
+    }
+
+    template<typename iter_t,
+             typename adapt_t,
+             typename val_t,
+             typename mod_t>
+    val_t interp(iter_t begin,
+                 iter_t end,
+                 adapt_t adapt,
+                 const std::vector<val_t> &vals,
+                 double x,
+                 double y,
+                 mod_t mod = mod_t()) {
+      std::vector<carve::geom2d::P2> s;
+      s.reserve(std::distance(begin, end));
+      std::transform(begin, end, std::back_inserter(s), adapt);
+      std::vector<double> weight = polyInterpolate(s, carve::geom::VECTOR(x, y));
+
+      val_t v;
+      for (size_t z = 0; z < weight.size(); z++) {
+        v += weight[z] * vals[z];
+      }
+
+      return mod(v);
+    }
+
+    template<typename iter_t,
+             typename adapt_t,
+             typename val_t>
+    val_t interp(iter_t begin,
+                 iter_t end,
+                 adapt_t adapt,
+                 const std::vector<val_t> &vals,
+                 double x,
+                 double y) {
+      return interp(begin, end, adapt, vals, x, y, identity_t<val_t>());
+    }
+    
+    template<typename vertex_t,
+             typename adapt_t,
+             typename val_t,
+             typename mod_t>
+    val_t interp(const std::vector<vertex_t> &poly,
+                 adapt_t adapt,
+                 const std::vector<val_t> &vals,
+                 double x,
+                 double y,
+                 mod_t mod = mod_t()) {
+      return interp(poly.begin(), poly.end(), adapt, vals, x, y, mod);
+    }
+
+    template<typename vertex_t,
+             typename adapt_t,
+             typename val_t>
+    val_t interp(const std::vector<vertex_t> &poly,
+                 adapt_t adapt,
+                 const std::vector<val_t> &vals,
+                 double x,
+                 double y) {
+      return interp(poly.begin(), poly.end(), adapt, vals, x, y, identity_t<val_t>());
+    }
+    
+    template<typename val_t,
+             typename mod_t>
+    val_t interp(const std::vector<carve::geom2d::P2> &poly,
+                 const std::vector<val_t> &vals,
+                 double x,
+                 double y,
+                 mod_t mod = mod_t()) {
+      std::vector<double> weight = polyInterpolate(poly, carve::geom::VECTOR(x, y));
+
+      val_t v;
+      for (size_t z = 0; z < weight.size(); z++) {
+        v += weight[z] * vals[z];
+      }
+
+      return mod(v);
+    }
+
+    template<typename val_t>
+    val_t interp(const std::vector<carve::geom2d::P2> &poly,
+                 const std::vector<val_t> &vals,
+                 double x,
+                 double y) {
+      return interp(poly, vals, x, y, identity_t<val_t>());
+    }
+
+    class Interpolator {
+    public:
+      virtual void interpolate(const carve::mesh::MeshSet<3>::face_t *new_face,
+                               const carve::mesh::MeshSet<3>::face_t *orig_face,
+                               bool flipped) =0;
+
+      Interpolator() {
+      }
+
+      virtual ~Interpolator() {
+      }
+
+      class Hook : public carve::csg::CSG::Hook {
+        Interpolator *interpolator;
+      public:
+        virtual void resultFace(const carve::mesh::MeshSet<3>::face_t *new_face,
+                                const carve::mesh::MeshSet<3>::face_t *orig_face,
+                                bool flipped) {
+          interpolator->interpolate(new_face, orig_face, flipped);
+        }
+
+        Hook(Interpolator *_interpolator) : interpolator(_interpolator) {
+        }
+
+        virtual ~Hook() {
+        }
+      };
+
+      void installHooks(carve::csg::CSG &csg) {
+        csg.hooks.registerHook(new Hook(this), carve::csg::CSG::Hooks::RESULT_FACE_BIT);
+      }
+    };
+
+    template<typename attr_t>
+    class FaceVertexAttr : public Interpolator {
+
+    protected:
+      struct fv_hash {
+        size_t operator()(const std::pair<const carve::mesh::MeshSet<3>::face_t *, unsigned> &v) const {
+          return size_t(v.first) ^ size_t(v.second);
+        }
+      };
+
+      typedef std::unordered_map<const carve::mesh::MeshSet<3>::vertex_t *, attr_t> attrvmap_t;
+      typedef std::unordered_map<std::pair<const carve::mesh::MeshSet<3>::face_t *, unsigned>, attr_t, fv_hash> attrmap_t;
+
+      attrmap_t attrs;
+
+    public:
+      bool hasAttribute(const carve::mesh::MeshSet<3>::face_t *f, unsigned v) {
+        return attrs.find(std::make_pair(f, v)) != attrs.end();
+      }
+
+      attr_t getAttribute(const carve::mesh::MeshSet<3>::face_t *f, unsigned v, const attr_t &def = attr_t()) {
+        typename attrmap_t::const_iterator fv = attrs.find(std::make_pair(f, v));
+        if (fv != attrs.end()) {
+          return (*fv).second;
+        }
+        return def;
+      }
+
+      void setAttribute(const carve::mesh::MeshSet<3>::face_t *f, unsigned v, const attr_t &attr) {
+        attrs[std::make_pair(f, v)] = attr;
+      }
+
+      virtual void interpolate(const carve::mesh::MeshSet<3>::face_t *new_face,
+                               const carve::mesh::MeshSet<3>::face_t *orig_face,
+                               bool flipped) {
+        std::vector<attr_t> vertex_attrs;
+        attrvmap_t base_attrs;
+        vertex_attrs.reserve(orig_face->nVertices());
+
+        for (carve::mesh::MeshSet<3>::face_t::const_edge_iter_t e = orig_face->begin(); e != orig_face->end(); ++e) {
+          typename attrmap_t::const_iterator a = attrs.find(std::make_pair(orig_face, e.idx()));
+          if (a == attrs.end()) return;
+          vertex_attrs.push_back((*a).second);
+          base_attrs[e->vert] = vertex_attrs.back();
+        }
+
+        for (carve::mesh::MeshSet<3>::face_t::const_edge_iter_t e = new_face->begin(); e != new_face->end(); ++e) {
+          const carve::mesh::MeshSet<3>::vertex_t *vertex = e->vert;
+          typename attrvmap_t::const_iterator b = base_attrs.find(vertex);
+          if (b != base_attrs.end()) {
+            attrs[std::make_pair(new_face, e.idx())] = (*b).second;
+          } else {
+            carve::geom2d::P2 p = orig_face->project(e->vert->v);
+            attr_t attr = interp(orig_face->begin(),
+                                 orig_face->end(),
+                                 orig_face->projector(),
+                                 vertex_attrs,
+                                 p.x,
+                                 p.y);
+            attrs[std::make_pair(new_face, e.idx())] = attr;
+          }
+        }
+      }
+
+      FaceVertexAttr() : Interpolator() {
+      }
+
+      virtual ~FaceVertexAttr() {
+      }
+
+    };
+
+
+    template<typename attr_t>
+    class FaceAttr : public Interpolator {
+
+    protected:
+      struct f_hash {
+        size_t operator()(const carve::mesh::MeshSet<3>::face_t * const &f) const {
+          return size_t(f);
+        }
+      };
+
+      typedef std::unordered_map<const carve::mesh::MeshSet<3>::face_t *, attr_t, f_hash> attrmap_t;
+
+      attrmap_t attrs;
+
+    public:
+      bool hasAttribute(const carve::mesh::MeshSet<3>::face_t *f) {
+        return attrs.find(f) != attrs.end();
+      }
+
+      attr_t getAttribute(const carve::mesh::MeshSet<3>::face_t *f, const attr_t &def = attr_t()) {
+        typename attrmap_t::const_iterator i = attrs.find(f);
+        if (i != attrs.end()) {
+          return (*i).second;
+        }
+        return def;
+      }
+
+      void setAttribute(const carve::mesh::MeshSet<3>::face_t *f, const attr_t &attr) {
+        attrs[f] = attr;
+      }
+
+      virtual void interpolate(const carve::mesh::MeshSet<3>::face_t *new_face,
+                               const carve::mesh::MeshSet<3>::face_t *orig_face,
+                               bool flipped) {
+        typename attrmap_t::const_iterator i = attrs.find(orig_face);
+        if (i != attrs.end()) {
+          attrs[new_face] = (*i).second;
+        }
+      }
+
+      FaceAttr() : Interpolator() {
+      }
+
+      virtual ~FaceAttr() {
+      }
+
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/intersection.hpp b/extern/carve/include/carve/intersection.hpp
new file mode 100644
index 00000000000..1862a366abb
--- /dev/null
+++ b/extern/carve/include/carve/intersection.hpp
@@ -0,0 +1,267 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/collection_types.hpp>
+#include <carve/iobj.hpp>
+
+namespace carve {
+  namespace csg {
+
+    /** 
+     * \class Intersections
+     * \brief Storage for computed intersections between vertices, edges and faces.
+     * 
+     */
+    struct Intersections : public std::unordered_map<IObj, IObjVMapSmall, IObj_hash> {
+      typedef carve::mesh::MeshSet<3>::vertex_t vertex_t;
+      typedef carve::mesh::MeshSet<3>::edge_t   edge_t;
+      typedef carve::mesh::MeshSet<3>::face_t   face_t;
+
+      typedef std::unordered_map<IObj, IObjVMapSmall, IObj_hash> super;
+
+      ~Intersections() {
+      }
+
+      /** 
+       * \brief Record the position of intersection between a pair of intersection objects.
+       * 
+       * @param a The first intersecting object.
+       * @param b The second intersecting object.
+       * @param p The point of intersection.
+       */
+      void record(IObj a, IObj b, vertex_t *p) {
+        if (a > b) std::swap(a, b);
+        (*this)[a][b] = p;
+        (*this)[b][a] = p;
+      }
+
+      /** 
+       * \brief Test whether vertex \a v intersects face \a f.
+       * 
+       * @param v The vertex to test.
+       * @param f The face to test.
+       * 
+       * @return true, if \a v intersects \a f.
+       */
+      bool intersectsFace(vertex_t *v, face_t *f) const;
+
+      /** 
+       * \brief Collect sets of vertices, edges and faces that intersect \a obj
+       * 
+       * @param[in] obj The intersection object to search for intersections.
+       * @param[out] collect_v A vector of vertices intersecting \a obj.
+       * @param[out] collect_e A vector of edges intersecting \a obj.
+       * @param[out] collect_f A vector of faces intersecting \a obj.
+       */
+      void collect(const IObj &obj,
+                   std::vector<vertex_t *> *collect_v,
+                   std::vector<edge_t *> *collect_e,
+                   std::vector<face_t *> *collect_f) const;
+
+
+      /** 
+       * \brief Determine whether two intersection objects intersect.
+       * 
+       * @param a The first intersection object.
+       * @param b The second intersection object.
+       * 
+       * @return true, if \a a and \a b intersect.
+       */
+      bool intersectsExactly(const IObj &a, const IObj &b) {
+        Intersections::const_iterator i = find(a);
+        if (i == end()) return false;
+        return i->second.find(b) != i->second.end();
+      }
+
+      /** 
+       * \brief Determine whether an intersection object intersects a vertex.
+       * 
+       * @param a The intersection object.
+       * @param v The vertex.
+       * 
+       * @return true, if \a a and \a v intersect.
+       */
+      bool intersects(const IObj &a, vertex_t *v) {
+        Intersections::const_iterator i = find(a);
+        if (i == end()) return false;
+        if (i->second.find(v) != i->second.end()) return true;
+        return false;
+      }
+
+      /** 
+       * \brief Determine whether an intersection object intersects an edge.
+       * 
+       * @param a The intersection object.
+       * @param e The edge.
+       * 
+       * @return true, if \a a and \a e intersect (either on the edge,
+       *         or at either endpoint).
+       */
+      bool intersects(const IObj &a, edge_t *e) {
+        Intersections::const_iterator i = find(a);
+        if (i == end()) return false;
+        for (super::data_type::const_iterator j = i->second.begin(); j != i->second.end(); ++j) {
+          const IObj &obj = j->first;
+          switch (obj.obtype) {
+          case IObj::OBTYPE_VERTEX:
+            if (obj.vertex == e->v1() || obj.vertex == e->v2()) return true;
+            break;
+          case IObj::OBTYPE_EDGE:
+            if (obj.edge == e) return true;
+            break;
+          default:
+            break;
+          }
+        }
+        return false;
+      }
+
+      /** 
+       * \brief Determine whether an intersection object intersects a face.
+       * 
+       * @param a The intersection object.
+       * @param f The face.
+       * 
+       * @return true, if \a a and \a f intersect (either on the face,
+       *         or at any associated edge or vertex).
+       */
+      bool intersects(const IObj &a, face_t *f) {
+        Intersections::const_iterator i = find(a);
+        if (i == end()) return false;
+        if (i->second.find(f) != i->second.end()) return true;
+        edge_t *e = f->edge;
+        do {
+          if (i->second.find(e) != i->second.end()) return true;
+          if (i->second.find(e->vert) != i->second.end()) return true;
+          e = e->next;
+        } while (e != f->edge);
+        return false;
+      }
+
+      /** 
+       * \brief Determine whether an edge intersects another edge.
+       * 
+       * @param e The edge.
+       * @param f The face.
+       * 
+       * @return true, if \a e and \a f intersect.
+       */
+      bool intersects(edge_t *e1, edge_t *e2) {
+        if (intersects(e1->v1(), e2) || intersects(e1->v2(), e2) || intersects(IObj(e1), e2)) return true;
+        return false;
+      }
+
+      /** 
+       * \brief Determine whether an edge intersects a face.
+       * 
+       * @param e The edge.
+       * @param f The face.
+       * 
+       * @return true, if \a e and \a f intersect.
+       */
+      bool intersects(edge_t *e, face_t *f) {
+        if (intersects(e->v1(), f) || intersects(e->v2(), f) || intersects(IObj(e), f)) return true;
+        return false;
+      }
+
+      /** 
+       * \brief Determine the faces intersected by an edge.
+       * 
+       * @tparam face_set_t A collection type holding face_t *
+       * @param[in] e The edge.
+       * @param[out] f The resulting set of faces.
+       */
+      template<typename face_set_t>
+      void intersectedFaces(edge_t *e, face_set_t &f) const {
+        std::vector<face_t *> intersected_faces;
+        std::vector<edge_t *> intersected_edges;
+        std::vector<vertex_t *> intersected_vertices;
+
+        collect(e, &intersected_vertices, &intersected_edges, &intersected_faces);
+
+        for (unsigned i = 0; i < intersected_vertices.size(); ++i) {
+          facesForVertex(intersected_vertices[i], f);
+        }
+        for (unsigned i = 0; i < intersected_edges.size(); ++i) {
+          facesForEdge(intersected_edges[i], f);
+        }
+        f.insert(intersected_faces.begin(), intersected_faces.end());
+      }
+
+      /** 
+       * \brief Determine the faces intersected by a vertex.
+       * 
+       * @tparam face_set_t A collection type holding face_t *
+       * @param[in] v The vertex.
+       * @param[out] f The resulting set of faces.
+       */
+      template<typename face_set_t>
+      void intersectedFaces(vertex_t *v, face_set_t &f) const {
+        std::vector<face_t *> intersected_faces;
+        std::vector<edge_t *> intersected_edges;
+        std::vector<vertex_t *> intersected_vertices;
+
+        collect(v, &intersected_vertices, &intersected_edges, &intersected_faces);
+
+        for (unsigned i = 0; i < intersected_vertices.size(); ++i) {
+          facesForVertex(intersected_vertices[i], f);
+        }
+        for (unsigned i = 0; i < intersected_edges.size(); ++i) {
+          facesForEdge(intersected_edges[i], f);
+        }
+        f.insert(intersected_faces.begin(), intersected_faces.end());
+      }
+
+      /** 
+       * \brief Collect the set of faces that contain all vertices in \a verts.
+       * 
+       * @tparam vertex_set_t A collection type holding vertex_t *
+       * @tparam face_set_t A collection type holding face_t *
+       * @param[in] verts A set of vertices.
+       * @param[out] result The resulting set of faces.
+       */
+      template<typename vertex_set_t, typename face_set_t>
+      void commonFaces(const vertex_set_t &verts, face_set_t &result) {
+
+        std::set<face_t *> ifaces, temp, out;
+        typename vertex_set_t::const_iterator i = verts.begin();
+        if (i == verts.end()) return;
+        intersectedFaces((*i), ifaces);
+        while (++i != verts.end()) {
+          temp.clear();
+          intersectedFaces((*i), temp);
+
+          out.clear();
+          std::set_intersection(temp.begin(), temp.end(),
+                                ifaces.begin(), ifaces.end(),
+                                set_inserter(out));
+          ifaces.swap(out);
+        }
+        std::copy(ifaces.begin(), ifaces.end(), set_inserter(result));
+      }
+
+      void clear() {
+        super::clear();
+      }
+
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/iobj.hpp b/extern/carve/include/carve/iobj.hpp
new file mode 100644
index 00000000000..13d88ec820b
--- /dev/null
+++ b/extern/carve/include/carve/iobj.hpp
@@ -0,0 +1,106 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+namespace carve {
+  namespace csg {
+    struct IObj {
+      enum {
+        OBTYPE_NONE   = 0,
+        OBTYPE_VERTEX = 1,
+        OBTYPE_EDGE   = 2,
+        OBTYPE_FACE   = 4
+      } obtype;
+
+      union {
+        carve::mesh::MeshSet<3>::vertex_t *vertex;
+        carve::mesh::MeshSet<3>::edge_t *edge;
+        carve::mesh::MeshSet<3>::face_t *face;
+        intptr_t val;
+      };
+
+      IObj() : obtype(OBTYPE_NONE), val(0) { }
+      IObj(carve::mesh::MeshSet<3>::vertex_t *v) : obtype(OBTYPE_VERTEX), vertex(v) { }
+      IObj(carve::mesh::MeshSet<3>::edge_t *e) : obtype(OBTYPE_EDGE), edge(e) { }
+      IObj(carve::mesh::MeshSet<3>::face_t *f) : obtype(OBTYPE_FACE), face(f) { }
+      char typeChar() const { return "NVExF"[obtype]; }
+    };
+
+
+
+    struct IObj_hash {
+      inline size_t operator()(const IObj &i) const {
+        return (size_t)i.val;
+      }
+      inline size_t operator()(const std::pair<const IObj, const IObj> &i) const {
+        return (size_t)i.first.val ^ (size_t)i.second.val;
+      }
+    };
+
+
+
+    typedef std::unordered_set<std::pair<const IObj, const IObj>, IObj_hash> IObjPairSet;
+
+    typedef std::unordered_map<IObj, carve::mesh::MeshSet<3>::vertex_t *, IObj_hash> IObjVMap;
+    typedef std::map<IObj, carve::mesh::MeshSet<3>::vertex_t *> IObjVMapSmall;
+
+    class VertexIntersections :
+      public std::unordered_map<carve::mesh::MeshSet<3>::vertex_t *, IObjPairSet> {
+    };
+
+
+
+    static inline bool operator==(const carve::csg::IObj &a, const carve::csg::IObj &b) {
+      return a.obtype == b.obtype && a.val == b.val;
+    }
+
+    static inline bool operator!=(const carve::csg::IObj &a, const carve::csg::IObj &b) {
+      return a.obtype != b.obtype || a.val != b.val;
+    }
+
+    static inline bool operator<(const carve::csg::IObj &a, const carve::csg::IObj &b) {
+      return a.obtype < b.obtype || (a.obtype == b.obtype && a.val < b.val);
+    }
+
+    static inline bool operator<=(const carve::csg::IObj &a, const carve::csg::IObj &b) {
+      return a.obtype < b.obtype || (a.obtype == b.obtype && a.val <= b.val);
+    }
+
+    static inline bool operator>(const carve::csg::IObj &a, const carve::csg::IObj &b) {
+      return a.obtype > b.obtype || (a.obtype == b.obtype && a.val > b.val);
+    }
+
+    static inline bool operator>=(const carve::csg::IObj &a, const carve::csg::IObj &b) {
+      return a.obtype > b.obtype || (a.obtype == b.obtype && a.val >= b.val);
+    }
+
+    static inline std::ostream &operator<<(std::ostream &o, const carve::csg::IObj &a) {
+      switch (a.obtype) {
+        case carve::csg::IObj::OBTYPE_NONE:   o << "NONE{}"; break;
+        case carve::csg::IObj::OBTYPE_VERTEX: o << "VERT{" << a.vertex << "}"; break;
+        case carve::csg::IObj::OBTYPE_EDGE:   o << "EDGE{" << a.edge << "}"; break;
+        case carve::csg::IObj::OBTYPE_FACE:   o << "FACE{" << a.face << "}"; break;
+      }
+      return o;
+    }
+
+  }
+}
+
diff --git a/extern/carve/include/carve/kd_node.hpp b/extern/carve/include/carve/kd_node.hpp
new file mode 100644
index 00000000000..f62584d50c2
--- /dev/null
+++ b/extern/carve/include/carve/kd_node.hpp
@@ -0,0 +1,308 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/geom.hpp>
+#include <carve/aabb.hpp>
+
+#include <queue>
+#include <list>
+#include <limits>
+
+namespace carve {
+  namespace geom {
+    template<unsigned ndim,
+             typename data_t,
+             typename inserter_t,
+             typename aabb_calc_t>
+    class kd_node {
+      kd_node(const kd_node &);
+      kd_node &operator=(const kd_node &);
+
+    public:
+      kd_node *c_neg;
+      kd_node *c_pos;
+      kd_node *parent;
+      axis_pos splitpos;
+
+      typedef vector<ndim> vector_t;
+      typedef std::list<data_t> container_t;
+
+      container_t data;
+
+      kd_node(kd_node *_parent = NULL) : c_neg(NULL), c_pos(NULL), parent(_parent), splitpos(0, 0.0) {
+      }
+
+      ~kd_node() {
+        if (c_neg) delete c_neg;
+        if (c_pos) delete c_pos;
+      }
+
+      template<typename visitor_t>
+      void closeNodes(const vector_t &p, double d, visitor_t &visit) const {
+        if (c_neg) {
+          double delta = splitpos.pos - p[splitpos.axis];
+          if (delta <= d) c_neg->closeNodes(p, d, visit);
+          if (delta >= -d) c_pos->closeNodes(p, d, visit);
+        } else {
+          visit(this);
+        }
+      }
+
+      void removeData(const data_t &d) {
+        typename container_t::iterator i = std::find(data.begin(), data.end(), d);
+
+        if (i != data.end()) {
+          data.erase(i);
+        }
+      }
+
+      void addData(const data_t &d) {
+        data.push_back(d);
+      }
+
+      void insert(const data_t &data, inserter_t &inserter) {
+        inserter.insert(this, data);
+      }
+
+      void insert(const data_t &data) {
+        inserter_t inserter;
+        insert(data, inserter);
+      }
+
+      void remove(const data_t &data, inserter_t &inserter) {
+        inserter.remove(this, data);
+      }
+
+      void remove(const data_t &data) {
+        inserter_t inserter;
+        remove(data, inserter);
+      }
+
+      carve::geom::aabb<ndim> nodeAABB() const {
+        carve::geom::aabb<ndim> aabb;
+        if (c_neg) {
+          aabb = c_neg->nodeAABB();
+          aabb.unionAABB(c_pos->nodeAABB());
+        } else {
+          if (data.size()) {
+            typename container_t::const_iterator i = data.begin();
+            aabb = aabb_calc_t()(*i);
+            while (i != data.end()) {
+              aabb.unionAABB(aabb_calc_t()(*i));
+              ++i;
+            }
+          }
+        }
+        return aabb;
+      }
+
+      bool split(axis_pos split_at, inserter_t &inserter) {
+        if (c_neg) {
+          // already split
+          return false;
+        }
+
+        c_neg = new kd_node(this);
+        c_pos = new kd_node(this);
+
+        // choose an axis and split point.
+        splitpos = split_at;
+
+        carve::geom::aabb<ndim> aabb;
+
+        if (splitpos.axis < 0 ||
+            splitpos.axis >= ndim ||
+            splitpos.pos == std::numeric_limits<double>::max()) {
+          // need an aabb
+          if (data.size()) {
+            typename container_t::const_iterator i = data.begin();
+            aabb = aabb_calc_t()(*i);
+            while (i != data.end()) {
+              aabb.unionAABB(aabb_calc_t()(*i));
+              ++i;
+            }
+          }
+        }
+
+        if (splitpos.axis < 0 || splitpos.axis >= ndim) {
+
+          // choose an axis;
+
+          // if no axis was specified, force calculation of the split position.
+          splitpos.pos = std::numeric_limits<double>::max();
+
+          // choose the axis of the AABB with the biggest extent.
+          splitpos.axis = largestAxis(aabb.extent);
+
+          if (parent && splitpos.axis == parent->splitpos.axis) {
+            // but don't choose the same axis as the parent node;
+            // choose the axis with the second greatest AABB extent.
+            double e = -1.0;
+            int a = -1;
+            for (unsigned i = 0; i < ndim; ++i) {
+              if (i == splitpos.axis) continue;
+              if (e < aabb.extent[i]) { a = i; e = aabb.extent[i]; }
+            }
+            if (a != -1) {
+              splitpos.axis = a;
+            }
+          }
+        }
+
+        if (splitpos.pos == std::numeric_limits<double>::max()) {
+          carve::geom::vector<ndim> min = aabb.min();
+          carve::geom::vector<ndim> max = aabb.max();
+          splitpos.pos = aabb.pos.v[splitpos.axis];
+        }
+
+        inserter.propagate(this);
+
+        return true;
+      }
+
+      bool split(axis_pos split_at = axis_pos(-1, std::numeric_limits<double>::max())) {
+        inserter_t inserter;
+        return split(split_at, inserter);
+      }
+
+      void splitn(int num, inserter_t &inserter) {
+        if (num <= 0) return;
+        if (!c_neg) {
+          split(inserter);
+        }
+        if (c_pos) c_pos->splitn(num-1, inserter);
+        if (c_neg) c_neg->splitn(num-1, inserter);
+      }
+
+      void splitn(int num) {
+        inserter_t inserter;
+        splitn(num, inserter);
+      }
+
+      template<typename split_t>
+      void splitn(int num, split_t splitter, inserter_t &inserter) {
+        if (num <= 0) return;
+        if (!c_neg) {
+          split(inserter, splitter(this));
+        }
+        if (c_pos) c_pos->splitn(num-1, inserter, splitter);
+        if (c_neg) c_neg->splitn(num-1, inserter, splitter);
+      }
+
+      template<typename split_t>
+      void splitn(int num, split_t splitter) {
+        inserter_t inserter;
+        splitn(num, splitter, inserter);
+      }
+
+      template<typename pred_t>
+      void splitpred(pred_t pred, inserter_t &inserter, int depth = 0) {
+        if (!c_neg) {
+          axis_pos splitpos(-1, std::numeric_limits<double>::max());
+          if (!pred(this, depth, splitpos)) return;
+          split(splitpos, inserter);
+        }
+        if (c_pos) c_pos->splitpred(pred, inserter, depth + 1);
+        if (c_neg) c_neg->splitpred(pred, inserter, depth + 1);
+      }
+
+      template<typename pred_t>
+      void splitpred(pred_t pred, int depth = 0) {
+        inserter_t inserter;
+        splitpred(pred, inserter, depth);
+      }
+
+      // distance_t must provide:
+      // double operator()(kd_node::data_t, vector<ndim>);
+      // double operator()(axis_pos, vector<ndim>);
+      template<typename distance_t>
+      struct near_point_query {
+
+        // q_t - the priority queue value type.
+        // q_t.first:  distance from object to query point.
+        // q_t.second: pointer to object
+        typedef std::pair<double, const typename kd_node::data_t *> q_t;
+
+        // the queue priority should sort from smallest distance to largest, and on equal distance, by object pointer.
+        struct pcmp {
+          bool operator()(const q_t &a, const q_t &b) {
+            return (a.first > b.first) || ((a.first == b.first) && (a.second < b.second));
+          }
+        };
+
+        vector<ndim> point;
+        const kd_node *node;
+        std::priority_queue<q_t, std::vector<q_t>, pcmp> pq;
+
+        distance_t dist;
+        double dist_to_parent_split;
+
+        void addToPQ(kd_node *node) {
+          if (node->c_neg) {
+            addToPQ(node->c_neg);
+            addToPQ(node->c_pos);
+          } else {
+            for (typename kd_node::container_t::const_iterator i = node->data.begin(); i != node->data.end(); ++i) {
+              double d = dist((*i), point);
+              pq.push(std::make_pair(d, &(*i)));
+            }
+          }
+        }
+
+        const typename kd_node::data_t *next() {
+          while (1) {
+            if (pq.size()) {
+              q_t t = pq.top();
+              if (!node->parent || t.first < dist_to_parent_split) {
+                pq.pop();
+                return t.second;
+              }
+            }
+
+            if (!node->parent) return NULL;
+
+            if (node->parent->c_neg == node) {
+              addToPQ(node->parent->c_pos);
+            } else {
+              addToPQ(node->parent->c_neg);
+            }
+
+            node = node->parent;
+            dist_to_parent_split = dist(node->splitpos, point);
+          }
+        }
+
+        near_point_query(const vector<ndim> _point, const kd_node *_node) : point(_point), node(_node), pq(), dist() {
+          while (node->c_neg) {
+            node = (point[node->axis] < node->pos) ? node->c_neg : node->c_pos;
+          }
+          if (node->parent) {
+            dist_to_parent_split = dist(node->parent->splitpos, point);
+          } else {
+            dist_to_parent_split = HUGE_VAL;
+          }
+          addToPQ(node);
+        }
+      };
+
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/math.hpp b/extern/carve/include/carve/math.hpp
new file mode 100644
index 00000000000..ec9ff0a9663
--- /dev/null
+++ b/extern/carve/include/carve/math.hpp
@@ -0,0 +1,60 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/math_constants.hpp>
+
+#include <math.h>
+
+namespace carve {
+  namespace geom {
+    template<unsigned ndim> struct vector;
+  }
+}
+
+namespace carve {
+  namespace math {
+    struct Matrix3;
+    int cubic_roots(double c3, double c2, double c1, double c0, double *roots);
+
+    void eigSolveSymmetric(const Matrix3 &m,
+                           double &l1, carve::geom::vector<3> &e1,
+                           double &l2, carve::geom::vector<3> &e2,
+                           double &l3, carve::geom::vector<3> &e3);
+
+    void eigSolve(const Matrix3 &m, double &l1, double &l2, double &l3);
+
+    static inline bool ZERO(double x) { return fabs(x) < carve::EPSILON; }
+
+    static inline double radians(double deg) { return deg * M_PI / 180.0; }
+    static inline double degrees(double rad) { return rad * 180.0 / M_PI; }
+
+    static inline double ANG(double x) {
+      return (x < 0) ? x + M_TWOPI : x;
+    }
+
+    template<typename T>
+    static inline const T &clamp(const T &val, const T &min, const T &max) {
+      if (val < min) return min;
+      if (val > max) return max;
+      return val;
+    }
+  }
+}
diff --git a/extern/carve/include/carve/math_constants.hpp b/extern/carve/include/carve/math_constants.hpp
new file mode 100644
index 00000000000..9d2c4fe0a46
--- /dev/null
+++ b/extern/carve/include/carve/math_constants.hpp
@@ -0,0 +1,33 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <math.h>
+
+#ifndef M_SQRT_3
+#define M_SQRT_3 1.73205080756887729352
+#endif
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+#ifndef M_TWOPI
+#define M_TWOPI (M_PI + M_PI)
+#endif
+
diff --git a/extern/carve/include/carve/matrix.hpp b/extern/carve/include/carve/matrix.hpp
new file mode 100644
index 00000000000..feb0cd72b97
--- /dev/null
+++ b/extern/carve/include/carve/matrix.hpp
@@ -0,0 +1,262 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <cstring>
+
+#include <carve/carve.hpp>
+
+#include <carve/math.hpp>
+#include <carve/geom.hpp>
+
+namespace carve {
+  namespace math {
+
+    struct Quaternion {
+      double x, y, z, w;
+
+      Quaternion(double _x, double _y, double _z, double _w) : x(_x), y(_y), z(_z), w(_w) {
+      }
+
+      Quaternion(double angle, const carve::geom::vector<3> &axis) {
+        double s = axis.length();
+        if (!carve::math::ZERO(s)) {
+          double c = 1.0 / s;
+          double omega = -0.5 * angle;
+          s = sin(omega);
+          x = axis.x * c * s;
+          y = axis.y * c * s;
+          z = axis.z * c * s;
+          w = cos(omega);
+          normalize();
+        } else {
+          x = y = z = 0.0;
+          w = 1.0;
+        }
+      }
+
+      double lengthSquared() const {
+        return x * x + y * y + z * z + w * w;
+      }
+
+      double length() const {
+        return sqrt(lengthSquared());
+      }
+
+      Quaternion normalized() const {
+        return Quaternion(*this).normalize();
+      }
+
+      Quaternion &normalize() {
+        double l = length();
+        if (l == 0.0) {
+          x = 1.0; y = 0.0; z = 0.0; w = 0.0;
+        } else {
+          x /= l; y /= l; z /= l; w /= l;
+        }
+        return *this;
+      }
+    };
+
+    struct Matrix3 {
+      // access: .m[col][row], .v[col * 4 + row], ._cr
+      union {
+        double m[3][3];
+        double v[9];
+        struct {
+          // transposed
+          double _11, _12, _13;
+          double _21, _22, _23;
+          double _31, _32, _33;
+        };
+      };
+      Matrix3(double __11, double __21, double __31,
+              double __12, double __22, double __32,
+              double __13, double __23, double __33) {
+        // nb, args are row major, storage is column major.
+        _11 = __11; _12 = __12; _13 = __13;
+        _21 = __21; _22 = __22; _23 = __23;
+        _31 = __31; _32 = __32; _33 = __33;
+      }
+      Matrix3(double _m[3][3]) {
+        std::memcpy(m, _m, sizeof(m));
+      }
+      Matrix3(double _v[9]) {
+        std::memcpy(v, _v, sizeof(v));
+      }
+      Matrix3() {
+        _11 = 1.00; _12 = 0.00; _13 = 0.00;
+        _21 = 0.00; _22 = 1.00; _23 = 0.00;
+        _31 = 0.00; _32 = 0.00; _33 = 1.00;
+      }
+    };
+
+    struct Matrix {
+      // access: .m[col][row], .v[col * 4 + row], ._cr
+      union {
+        double m[4][4];
+        double v[16];
+        struct {
+          // transposed
+          double _11, _12, _13, _14;
+          double _21, _22, _23, _24;
+          double _31, _32, _33, _34;
+          double _41, _42 ,_43, _44;
+        };
+      };
+      Matrix(double __11, double __21, double __31, double __41,
+             double __12, double __22, double __32, double __42,
+             double __13, double __23, double __33, double __43,
+             double __14, double __24, double __34, double __44) {
+        // nb, args are row major, storage is column major.
+        _11 = __11; _12 = __12; _13 = __13; _14 = __14;
+        _21 = __21; _22 = __22; _23 = __23; _24 = __24;
+        _31 = __31; _32 = __32; _33 = __33; _34 = __34;
+        _41 = __41; _42 = __42; _43 = __43; _44 = __44;
+      }
+      Matrix(double _m[4][4]) {
+        std::memcpy(m, _m, sizeof(m));
+      }
+      Matrix(double _v[16]) {
+        std::memcpy(v, _v, sizeof(v));
+      }
+      Matrix() {
+        _11 = 1.00; _12 = 0.00; _13 = 0.00; _14 = 0.00;
+        _21 = 0.00; _22 = 1.00; _23 = 0.00; _24 = 0.00;
+        _31 = 0.00; _32 = 0.00; _33 = 1.00; _34 = 0.00;
+        _41 = 0.00; _42 = 0.00; _43 = 0.00; _44 = 1.00;
+      }
+
+      static Matrix ROT(const Quaternion &q) {
+        const double w = q.w;
+        const double x = q.x;
+        const double y = q.y;
+        const double z = q.z;
+        return Matrix(1 - 2*y*y - 2*z*z,   2*x*y - 2*z*w,       2*x*z + 2*y*w,       0.0,  
+                      2*x*y + 2*z*w,       1 - 2*x*x - 2*z*z,   2*y*z - 2*x*w,       0.0,  
+                      2*x*z - 2*y*w,       2*y*z + 2*x*w,       1 - 2*x*x - 2*y*y,   0.0,  
+                      0.0,                 0.0,                 0.0,                 1.0);
+      }
+      static Matrix ROT(double angle, const carve::geom::vector<3> &axis) {
+        return ROT(Quaternion(angle, axis));
+      }
+      static Matrix ROT(double angle, double x, double y, double z) {
+        return ROT(Quaternion(angle, carve::geom::VECTOR(x, y, z)));
+      }
+      static Matrix TRANS(double x, double y, double z) {
+        return Matrix(1.0,   0.0,   0.0,   x,
+                      0.0,   1.0,   0.0,   y,
+                      0.0,   0.0,   1.0,   z,
+                      0.0,   0.0,   0.0,   1.0);
+      }
+      static Matrix TRANS(const carve::geom::vector<3> &v) {
+        return TRANS(v.x, v.y, v.z);
+      }
+      static Matrix SCALE(double x, double y, double z) {
+        return Matrix(x,     0.0,   0.0,   0.0,
+                      0.0,   y,     0.0,   0.0,
+                      0.0,   0.0,   z,     0.0,
+                      0.0,   0.0,   0.0,   1.0);
+      }
+      static Matrix SCALE(const carve::geom::vector<3> &v) {
+        return SCALE(v.x, v.y, v.z);
+      }
+      static Matrix IDENT() {
+        return Matrix(1.0,   0.0,   0.0,   0.0,
+                      0.0,   1.0,   0.0,   0.0,
+                      0.0,   0.0,   1.0,   0.0,
+                      0.0,   0.0,   0.0,   1.0);
+      }
+    };
+
+    static inline bool operator==(const Matrix &A, const Matrix &B) {
+      for (size_t i = 0; i < 16; ++i) if (A.v[i] != B.v[i]) return false;
+      return true;
+    }
+    static inline bool operator!=(const Matrix &A, const Matrix &B) {
+      return !(A == B);
+    }
+    static inline carve::geom::vector<3> operator*(const Matrix &A, const carve::geom::vector<3> &b) {
+      return carve::geom::VECTOR(
+                    A._11 * b.x + A._21 * b.y + A._31 * b.z + A._41,
+                    A._12 * b.x + A._22 * b.y + A._32 * b.z + A._42,
+                    A._13 * b.x + A._23 * b.y + A._33 * b.z + A._43
+                    );
+    }
+
+    static inline carve::geom::vector<3> &operator*=(carve::geom::vector<3> &b, const Matrix &A) {
+      b = A * b;
+      return b;
+    }
+
+    static inline carve::geom::vector<3> operator*(const Matrix3 &A, const carve::geom::vector<3> &b) {
+      return carve::geom::VECTOR(
+                    A._11 * b.x + A._21 * b.y + A._31 * b.z,
+                    A._12 * b.x + A._22 * b.y + A._32 * b.z,
+                    A._13 * b.x + A._23 * b.y + A._33 * b.z
+                    );
+    }
+
+    static inline carve::geom::vector<3> &operator*=(carve::geom::vector<3> &b, const Matrix3 &A) {
+      b = A * b;
+      return b;
+    }
+
+    static inline Matrix operator*(const Matrix &A, const Matrix &B) {
+      Matrix c;
+      for (int i = 0; i < 4; i++) {
+        for (int j = 0; j < 4; j++) {
+          c.m[i][j] = 0.0;
+          for (int k = 0; k < 4; k++) {
+            c.m[i][j] += A.m[k][j] * B.m[i][k];
+          }
+        }
+      }
+      return c;
+    }
+
+    static inline Matrix3 operator*(const Matrix3 &A, const Matrix3 &B) {
+      Matrix3 c;
+      for (int i = 0; i < 3; i++) {
+        for (int j = 0; j < 3; j++) {
+          c.m[i][j] = 0.0;
+          for (int k = 0; k < 3; k++) {
+            c.m[i][j] += A.m[k][j] * B.m[i][k];
+          }
+        }
+      }
+      return c;
+    }
+
+
+
+    struct matrix_transformation {
+      Matrix matrix;
+
+      matrix_transformation(const Matrix &_matrix) : matrix(_matrix) {
+      }
+
+      carve::geom::vector<3> operator()(const carve::geom::vector<3> &vector) const {
+        return matrix * vector;
+      }
+    };
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/mesh.hpp b/extern/carve/include/carve/mesh.hpp
new file mode 100644
index 00000000000..d4170e55133
--- /dev/null
+++ b/extern/carve/include/carve/mesh.hpp
@@ -0,0 +1,845 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/tag.hpp>
+#include <carve/djset.hpp>
+#include <carve/aabb.hpp>
+#include <carve/rtree.hpp>
+
+#include <iostream>
+
+namespace carve {
+  namespace poly {
+    class Polyhedron;
+  }
+
+  namespace mesh {
+
+
+    template<unsigned ndim> class Edge;
+    template<unsigned ndim> class Face;
+    template<unsigned ndim> class Mesh;
+    template<unsigned ndim> class MeshSet;
+
+
+
+    // A Vertex may participate in several meshes. If the Mesh belongs
+    // to a MeshSet, then the vertices come from the vertex_storage
+    // member of the MeshSet. This allows one to construct one or more
+    // Meshes out of sets of connected faces (possibly using vertices
+    // from a variety of MeshSets, and other storage), then create a
+    // MeshSet from the Mesh(es), causing the vertices to be
+    // collected, cloned and repointed into the MeshSet.
+
+    // Normally, in a half-edge structure, Vertex would have a member
+    // pointing to an incident edge, allowing the enumeration of
+    // adjacent faces and edges. Because we want to support vertex
+    // sharing between Meshes and groups of Faces, this is made more
+    // complex. If Vertex contained a list of incident edges, one from
+    // each disjoint face set, then this could be done (with the
+    // caveat that you'd need to pass in a Mesh pointer to the
+    // adjacency queries). However, it seems that this would
+    // unavoidably complicate the process of incorporating or removing
+    // a vertex into an edge.
+
+    // In most cases it is expected that a vertex will be arrived at
+    // via an edge or face in the mesh (implicit or explicit) of
+    // interest, so not storing this information will not hurt,
+    // overly.
+    template<unsigned ndim>
+    class Vertex : public tagable {
+    public:
+      typedef carve::geom::vector<ndim> vector_t;
+      typedef MeshSet<ndim> owner_t;
+      typedef carve::geom::aabb<ndim> aabb_t;
+
+      carve::geom::vector<ndim> v;
+
+      Vertex(const vector_t &_v) : tagable(), v(_v) {
+      }
+
+      Vertex() : tagable(), v() {
+      }
+
+      aabb_t getAABB() const {
+        return aabb_t(v, carve::geom::vector<ndim>::ZERO());
+      }
+    };
+
+
+
+    struct hash_vertex_pair {
+      template<unsigned ndim>
+      size_t operator()(const std::pair<Vertex<ndim> *, Vertex<ndim> *> &pair) const {
+        size_t r = (size_t)pair.first;
+        size_t s = (size_t)pair.second;
+        return r ^ ((s >> 16) | (s << 16));
+      }
+      template<unsigned ndim>
+      size_t operator()(const std::pair<const Vertex<ndim> *, const Vertex<ndim> *> &pair) const {
+        size_t r = (size_t)pair.first;
+        size_t s = (size_t)pair.second;
+        return r ^ ((s >> 16) | (s << 16));
+      }
+    };
+
+
+
+    struct vertex_distance {
+      template<unsigned ndim>
+      double operator()(const Vertex<ndim> &a, const Vertex<ndim> &b) const {
+        return carve::geom::distance(a.v, b.v);
+      }
+
+      template<unsigned ndim>
+      double operator()(const Vertex<ndim> *a, const Vertex<ndim> *b) const {
+        return carve::geom::distance(a->v, b->v);
+      }
+    };
+
+
+
+    namespace detail {
+      template<typename list_t> struct list_iter_t;
+      template<typename list_t, typename mapping_t> struct mapped_list_iter_t;
+    }
+
+
+
+    // The half-edge structure proper (Edge) is maintained by Face
+    // instances. Together with Face instances, the half-edge
+    // structure defines a simple mesh (either one or two faces
+    // incident on each edge).
+    template<unsigned ndim>
+    class Edge : public tagable {
+    public:
+      typedef Vertex<ndim> vertex_t;
+      typedef Face<ndim> face_t;
+
+      vertex_t *vert;
+      face_t *face;
+      Edge *prev, *next, *rev;
+
+    private:
+      static void _link(Edge *a, Edge *b) {
+        a->next = b; b->prev = a;
+      }
+
+      static void _freeloop(Edge *s) {
+        Edge *e = s;
+        do {
+          Edge *n = e->next;
+          delete e;
+          e = n;
+        } while (e != s);
+      }
+
+      static void _setloopface(Edge *s, face_t *f) {
+        Edge *e = s;
+        do {
+          e->face = f;
+          e = e->next;
+        } while (e != s);
+      }
+
+      static size_t _looplen(Edge *s) {
+        Edge *e = s;
+        face_t *f = s->face;
+        size_t c = 0;
+        do {
+          ++c;
+          CARVE_ASSERT(e->rev->rev == e);
+          CARVE_ASSERT(e->next->prev == e);
+          CARVE_ASSERT(e->face == f);
+          e = e->next;
+        } while (e != s);
+        return c;
+      }
+
+    public:
+      void validateLoop() {
+        Edge *e = this;
+        face_t *f = face;
+        size_t c = 0;
+        do {
+          ++c;
+          CARVE_ASSERT(e->rev == NULL || e->rev->rev == e);
+          CARVE_ASSERT(e->next == e || e->next->vert != e->vert);
+          CARVE_ASSERT(e->prev == e || e->prev->vert != e->vert);
+          CARVE_ASSERT(e->next->prev == e);
+          CARVE_ASSERT(e->prev->next == e);
+          CARVE_ASSERT(e->face == f);
+          e = e->next;
+        } while (e != this);
+        CARVE_ASSERT(f == NULL || c == f->n_edges);
+      }
+
+      size_t loopLen() {
+        return _looplen(this);
+      }
+
+      Edge *mergeFaces();
+
+      Edge *removeHalfEdge();
+
+      // Remove and delete this edge.
+      Edge *removeEdge();
+
+      // Unlink this edge from its containing edge loop. disconnect
+      // rev links. The rev links of the previous edge also change, as
+      // its successor vertex changes.
+      void unlink();
+
+      // Insert this edge into a loop before other. If edge was
+      // already in a loop, it needs to be removed first.
+      void insertBefore(Edge *other);
+
+      // Insert this edge into a loop after other. If edge was
+      // already in a loop, it needs to be removed first.
+      void insertAfter(Edge *other);
+
+      size_t loopSize() const;
+
+      vertex_t *v1() { return vert; }
+      vertex_t *v2() { return next->vert; }
+
+      const vertex_t *v1() const { return vert; }
+      const vertex_t *v2() const { return next->vert; }
+
+      Edge *perimNext() const;
+      Edge *perimPrev() const;
+
+      double length2() const {
+        return (v1()->v - v2()->v).length2();
+      }
+
+      double length() const {
+        return (v1()->v - v2()->v).length();
+      }
+
+      Edge(vertex_t *_vert, face_t *_face);
+
+      ~Edge();
+    };
+
+
+
+    // A Face contains a pointer to the beginning of the half-edge
+    // circular list that defines its boundary.
+    template<unsigned ndim>
+    class Face : public tagable {
+    public:
+      typedef Vertex<ndim> vertex_t;
+      typedef Edge<ndim> edge_t;
+      typedef Mesh<ndim> mesh_t;
+
+      typedef typename Vertex<ndim>::vector_t vector_t;
+      typedef carve::geom::aabb<ndim> aabb_t;
+      typedef carve::geom::plane<ndim> plane_t;
+      typedef carve::geom::vector<2> (*project_t)(const vector_t &);
+      typedef vector_t (*unproject_t)(const carve::geom::vector<2> &, const plane_t &);
+
+      struct vector_mapping {
+        typedef typename vertex_t::vector_t value_type;
+
+        value_type operator()(const carve::geom::vector<ndim> &v) const { return v; }
+        value_type operator()(const carve::geom::vector<ndim> *v) const { return *v; }
+        value_type operator()(const Edge<ndim> &e) const { return e.vert->v; }
+        value_type operator()(const Edge<ndim> *e) const { return e->vert->v; }
+        value_type operator()(const Vertex<ndim> &v) const { return v.v; }
+        value_type operator()(const Vertex<ndim> *v) const { return v->v; }
+      };
+
+      struct projection_mapping {
+        typedef carve::geom::vector<2> value_type;
+        project_t proj;
+        projection_mapping(project_t _proj) : proj(_proj) { }
+        value_type operator()(const carve::geom::vector<ndim> &v) const { return proj(v); }
+        value_type operator()(const carve::geom::vector<ndim> *v) const { return proj(*v); }
+        value_type operator()(const Edge<ndim> &e) const { return proj(e.vert->v); }
+        value_type operator()(const Edge<ndim> *e) const { return proj(e->vert->v); }
+        value_type operator()(const Vertex<ndim> &v) const { return proj(v.v); }
+        value_type operator()(const Vertex<ndim> *v) const { return proj(v->v); }
+      };
+
+      edge_t *edge;
+      size_t n_edges;
+      mesh_t *mesh;
+      size_t id;
+
+      plane_t plane;
+      project_t project;
+      unproject_t unproject;
+
+    private:
+      Face &operator=(const Face &other);
+
+    protected:
+      Face() : edge(NULL), n_edges(0), mesh(NULL), id(0), plane(), project(NULL), unproject(NULL) {
+      }
+
+      Face(const Face &other) :
+        edge(NULL), n_edges(other.n_edges), mesh(NULL), id(other.id),
+        plane(other.plane), project(other.project), unproject(other.unproject) {
+      }
+
+      project_t getProjector(bool positive_facing, int axis) const;
+      unproject_t getUnprojector(bool positive_facing, int axis) const;
+
+    public:
+      typedef detail::list_iter_t<Edge<ndim> > edge_iter_t;
+      typedef detail::list_iter_t<const Edge<ndim> > const_edge_iter_t;
+
+      edge_iter_t begin() { return edge_iter_t(edge, 0); }
+      edge_iter_t end() { return edge_iter_t(edge, n_edges); }
+
+      const_edge_iter_t begin() const { return const_edge_iter_t(edge, 0); }
+      const_edge_iter_t end() const { return const_edge_iter_t(edge, n_edges); }
+
+      bool containsPoint(const vector_t &p) const;
+      bool containsPointInProjection(const vector_t &p) const;
+      bool simpleLineSegmentIntersection(
+          const carve::geom::linesegment<ndim> &line,
+          vector_t &intersection) const;
+      IntersectionClass lineSegmentIntersection(
+          const carve::geom::linesegment<ndim> &line,
+          vector_t &intersection) const;
+
+      aabb_t getAABB() const;
+
+      bool recalc();
+
+      void clearEdges();
+
+      // build an edge loop in forward orientation from an iterator pair
+      template<typename iter_t>
+      void loopFwd(iter_t vbegin, iter_t vend);
+
+      // build an edge loop in reverse orientation from an iterator pair
+      template<typename iter_t>
+      void loopRev(iter_t vbegin, iter_t vend);
+
+      // initialize a face from an ordered list of vertices.
+      template<typename iter_t>
+      void init(iter_t begin, iter_t end);
+
+      // initialization of a triangular face.
+      void init(vertex_t *a, vertex_t *b, vertex_t *c);
+
+      // initialization of a quad face.
+      void init(vertex_t *a, vertex_t *b, vertex_t *c, vertex_t *d);
+
+      void getVertices(std::vector<vertex_t *> &verts) const;
+      void getProjectedVertices(std::vector<carve::geom::vector<2> > &verts) const;
+
+      projection_mapping projector() const {
+        return projection_mapping(project);
+      }
+
+      std::pair<double, double> rangeInDirection(const vector_t &v, const vector_t &b) const {
+        edge_t *e = edge;
+        double lo, hi;
+        lo = hi = carve::geom::dot(v, e->vert->v - b);
+        e = e->next;
+        for (; e != edge; e = e->next) {
+          double d = carve::geom::dot(v, e->vert->v - b);
+          lo = std::min(lo, d);
+          hi = std::max(hi, d);
+        }
+        return std::make_pair(lo, hi);
+      }
+
+      size_t nVertices() const {
+        return n_edges;
+      }
+
+      size_t nEdges() const {
+        return n_edges;
+      }
+
+      vector_t centroid() const;
+
+      static Face *closeLoop(edge_t *open_edge);
+
+      Face(edge_t *e) : edge(e), n_edges(0), mesh(NULL) {
+        do {
+          e->face = this;
+          n_edges++;
+          e = e->next;
+        } while (e != edge);
+        recalc();
+      }
+
+      Face(vertex_t *a, vertex_t *b, vertex_t *c) : edge(NULL), n_edges(0), mesh(NULL) {
+        init(a, b, c);
+        recalc();
+      }
+
+      Face(vertex_t *a, vertex_t *b, vertex_t *c, vertex_t *d) : edge(NULL), n_edges(0), mesh(NULL) {
+        init(a, b, c, d);
+        recalc();
+      }
+
+      template<typename iter_t>
+      Face(iter_t begin, iter_t end) : edge(NULL), n_edges(0), mesh(NULL) {
+        init(begin, end);
+        recalc();
+      }
+
+      template<typename iter_t>
+      Face *create(iter_t beg, iter_t end, bool reversed) const;
+
+      Face *clone(const vertex_t *old_base, vertex_t *new_base, std::unordered_map<const edge_t *, edge_t *> &edge_map) const;
+
+      void remove() {
+        edge_t *e = edge;
+        do {
+          if (e->rev) e->rev->rev = NULL;
+          e = e->next;
+        } while (e != edge);
+      }
+
+      void invert() {
+        // We invert the direction of the edges of the face in this
+        // way so that the edge rev pointers (if any) are still
+        // correct. It is expected that invert() will be called on
+        // every other face in the mesh, too, otherwise everything
+        // will get messed up.
+
+        {
+          // advance vertices.
+          edge_t *e = edge;
+          vertex_t *va = e->vert;
+          do {
+            e->vert = e->next->vert;
+            e = e->next;
+          } while (e != edge);
+          edge->prev->vert = va;
+        }
+
+        {
+          // swap prev and next pointers.
+          edge_t *e = edge;
+          do {
+            edge_t *n = e->next;
+            std::swap(e->prev, e->next);
+            e = n;
+          } while (e != edge);
+        }
+
+        plane.negate();
+
+        int da = carve::geom::largestAxis(plane.N);
+
+        project = getProjector(plane.N.v[da] > 0, da);
+        unproject = getUnprojector(plane.N.v[da] > 0, da);
+      }
+
+      void canonicalize();
+
+      ~Face() {
+        clearEdges();
+      }
+    };
+
+
+
+    namespace detail {
+      class FaceStitcher {
+        typedef Vertex<3> vertex_t;
+        typedef Edge<3> edge_t;
+        typedef Face<3> face_t;
+
+        typedef std::pair<const vertex_t *, const vertex_t *> vpair_t;
+        typedef std::list<edge_t *> edgelist_t;
+        typedef std::unordered_map<vpair_t, edgelist_t, carve::mesh::hash_vertex_pair> edge_map_t;
+        typedef std::unordered_map<const vertex_t *, std::set<const vertex_t *> > edge_graph_t;
+
+        edge_map_t edges;
+        edge_map_t complex_edges;
+
+        carve::djset::djset face_groups;
+        std::vector<bool> is_open;
+
+        edge_graph_t edge_graph;
+
+        struct EdgeOrderData {
+          size_t group_id;
+          bool is_reversed;
+          carve::geom::vector<3> face_dir;
+          edge_t *edge;
+
+          EdgeOrderData(edge_t *_edge, size_t _group_id, bool _is_reversed) :
+            group_id(_group_id),
+            is_reversed(_is_reversed) {
+            if (is_reversed) {
+              face_dir = -(_edge->face->plane.N);
+            } else {
+              face_dir =  (_edge->face->plane.N);
+            }
+            edge = _edge;
+          }
+
+          struct TestGroups {
+            size_t fwd, rev;
+
+            TestGroups(size_t _fwd, size_t _rev) : fwd(_fwd), rev(_rev) {
+            }
+
+            bool operator()(const EdgeOrderData &eo) const {
+              return eo.group_id == (eo.is_reversed ? rev : fwd);
+            }
+          };
+
+          struct Cmp {
+            carve::geom::vector<3> edge_dir;
+            carve::geom::vector<3> base_dir;
+
+            Cmp(const carve::geom::vector<3> &_edge_dir,
+                const carve::geom::vector<3> &_base_dir) :
+              edge_dir(_edge_dir),
+              base_dir(_base_dir) {
+            }
+            bool operator()(const EdgeOrderData &a, const EdgeOrderData &b) const;
+          };
+        };
+
+        void extractConnectedEdges(std::vector<const vertex_t *>::iterator begin,
+                                   std::vector<const vertex_t *>::iterator end,
+                                   std::vector<std::vector<Edge<3> *> > &efwd,
+                                   std::vector<std::vector<Edge<3> *> > &erev);
+
+        size_t faceGroupID(const Face<3> *face);
+        size_t faceGroupID(const Edge<3> *edge);
+
+        void resolveOpenEdges();
+
+        void fuseEdges(std::vector<Edge<3> *> &fwd,
+                       std::vector<Edge<3> *> &rev);
+
+        void joinGroups(std::vector<std::vector<Edge<3> *> > &efwd,
+                        std::vector<std::vector<Edge<3> *> > &erev,
+                        size_t fwd_grp,
+                        size_t rev_grp);
+
+        void matchOrderedEdges(const std::vector<std::vector<EdgeOrderData> >::iterator begin,
+                               const std::vector<std::vector<EdgeOrderData> >::iterator end,
+                               std::vector<std::vector<Edge<3> *> > &efwd,
+                               std::vector<std::vector<Edge<3> *> > &erev);
+
+        void reorder(std::vector<EdgeOrderData> &ordering, size_t fwd_grp);
+
+        void orderForwardAndReverseEdges(std::vector<std::vector<Edge<3> *> > &efwd,
+                                         std::vector<std::vector<Edge<3> *> > &erev,
+                                         std::vector<std::vector<EdgeOrderData> > &result);
+
+        void edgeIncidentGroups(const vpair_t &e,
+                                const edge_map_t &all_edges,
+                                std::pair<std::set<size_t>, std::set<size_t> > &groups);
+
+        void buildEdgeGraph(const edge_map_t &all_edges);
+        void extractPath(std::vector<const vertex_t *> &path);
+        void removePath(const std::vector<const vertex_t *> &path);
+        void matchSimpleEdges();
+        void construct();
+
+        template<typename iter_t>
+        void initEdges(iter_t begin, iter_t end);
+
+        template<typename iter_t>
+        void build(iter_t begin, iter_t end, std::vector<Mesh<3> *> &meshes);
+
+      public:
+        template<typename iter_t>
+        void create(iter_t begin, iter_t end, std::vector<Mesh<3> *> &meshes);
+      };
+    }
+
+
+
+    // A Mesh is a connected set of faces. It may be open (some edges
+    // have NULL rev members), or closed. On destruction, a Mesh
+    // should free its Faces (which will in turn free Edges, but not
+    // Vertices).  A Mesh is edge-connected, which is to say that each
+    // face in the mesh shares an edge with at least one other face in
+    // the mesh. Touching at a vertex is not sufficient. This means
+    // that the perimeter of an open mesh visits each vertex no more
+    // than once.
+    template<unsigned ndim>
+    class Mesh {
+    public:
+      typedef Vertex<ndim> vertex_t;
+      typedef Edge<ndim> edge_t;
+      typedef Face<ndim> face_t;
+      typedef carve::geom::aabb<ndim> aabb_t;
+      typedef MeshSet<ndim> meshset_t;
+
+      std::vector<face_t *> faces;
+
+      // open_edges is a vector of all the edges in the mesh that
+      // don't have a matching edge in the opposite direction.
+      std::vector<edge_t *> open_edges;
+
+      // closed_edges is a vector of all the edges in the mesh that
+      // have a matching edge in the opposite direction, and whose
+      // address is lower than their counterpart. (i.e. for each pair
+      // of adjoining faces, one of the two half edges is stored in
+      // closed_edges).
+      std::vector<edge_t *> closed_edges;
+
+      bool is_negative;
+
+      meshset_t *meshset;
+
+    protected:
+      Mesh(std::vector<face_t *> &_faces,
+           std::vector<edge_t *> &_open_edges,
+           std::vector<edge_t *> &_closed_edges,
+           bool _is_negative);
+
+    public:
+      Mesh(std::vector<face_t *> &_faces);
+
+      ~Mesh();
+
+      template<typename iter_t>
+      static void create(iter_t begin, iter_t end, std::vector<Mesh<ndim> *> &meshes);
+
+      aabb_t getAABB() const {
+        return aabb_t(faces.begin(), faces.end());
+      }
+
+      bool isClosed() const {
+        return open_edges.size() == 0;
+      }
+
+      bool isNegative() const {
+        return is_negative;
+      }
+
+      double volume() const {
+        if (is_negative || !faces.size()) return 0.0;
+
+        double vol = 0.0;
+        typename vertex_t::vector_t origin = faces[0]->edge->vert->v;
+
+        for (size_t f = 0; f < faces.size(); ++f) {
+          face_t *face = faces[f];
+          edge_t *e1 = face->edge;
+          for (edge_t *e2 = e1->next ;e2->next != e1; e2 = e2->next) {
+            vol += carve::geom3d::tetrahedronVolume(e1->vert->v, e2->vert->v, e2->next->vert->v, origin);
+          }
+        }
+        return vol;
+      }
+
+      struct IsClosed {
+        bool operator()(const Mesh &mesh) const { return mesh.isClosed(); }
+        bool operator()(const Mesh *mesh) const { return mesh->isClosed(); }
+      };
+
+      struct IsNegative {
+        bool operator()(const Mesh &mesh) const { return mesh.isNegative(); }
+        bool operator()(const Mesh *mesh) const { return mesh->isNegative(); }
+      };
+
+      void cacheEdges();
+
+      void calcOrientation();
+
+      void recalc() {
+        for (size_t i = 0; i < faces.size(); ++i) faces[i]->recalc();
+        calcOrientation();
+      }
+
+      void invert() {
+        for (size_t i = 0; i < faces.size(); ++i) {
+          faces[i]->invert();
+        }
+        if (isClosed()) is_negative = !is_negative;
+      }
+
+      Mesh *clone(const vertex_t *old_base, vertex_t *new_base) const;
+    };
+
+    // A MeshSet manages vertex storage, and a collection of meshes.
+    // It should be easy to turn a vertex pointer into its index in
+    // its MeshSet vertex_storage.
+    template<unsigned ndim>
+    class MeshSet {
+      MeshSet();
+      MeshSet(const MeshSet &);
+      MeshSet &operator=(const MeshSet &);
+
+      template<typename iter_t>
+      void _init_from_faces(iter_t begin, iter_t end);
+
+    public:
+      typedef Vertex<ndim> vertex_t;
+      typedef Edge<ndim> edge_t;
+      typedef Face<ndim> face_t;
+      typedef Mesh<ndim> mesh_t;
+      typedef carve::geom::aabb<ndim> aabb_t;
+
+      std::vector<vertex_t> vertex_storage;
+      std::vector<mesh_t *> meshes;
+
+    public:
+      template<typename face_type>
+      struct FaceIter : public std::iterator<std::random_access_iterator_tag, face_type> {
+        typedef std::iterator<std::random_access_iterator_tag, face_type> super;
+        typedef typename super::difference_type difference_type;
+
+        const MeshSet<ndim> *obj;
+        size_t mesh, face;
+
+        FaceIter(const MeshSet<ndim> *_obj, size_t _mesh, size_t _face);
+
+        void fwd(size_t n);
+        void rev(size_t n);
+        void adv(int n);
+
+        FaceIter operator++(int) { FaceIter tmp = *this; tmp.fwd(1); return tmp; }
+        FaceIter operator+(int v) { FaceIter tmp = *this; tmp.adv(v); return tmp; }
+        FaceIter &operator++() { fwd(1); return *this; }
+        FaceIter &operator+=(int v) { adv(v); return *this; }
+
+        FaceIter operator--(int) { FaceIter tmp = *this; tmp.rev(1); return tmp; }
+        FaceIter operator-(int v) { FaceIter tmp = *this; tmp.adv(-v); return tmp; }
+        FaceIter &operator--() { rev(1); return *this; }
+        FaceIter &operator-=(int v) { adv(-v); return *this; }
+
+        difference_type operator-(const FaceIter &other) const;
+
+        bool operator==(const FaceIter &other) const {
+          return obj == other.obj && mesh == other.mesh && face == other.face;
+        }
+        bool operator!=(const FaceIter &other) const {
+          return !(*this == other);
+        }
+        bool operator<(const FaceIter &other) const {
+          CARVE_ASSERT(obj == other.obj);
+          return mesh < other.mesh || (mesh == other.mesh && face < other.face);
+        }
+        bool operator>(const FaceIter &other) const {
+          return other < *this;
+        }
+        bool operator<=(const FaceIter &other) const {
+          return !(other < *this);
+        }
+        bool operator>=(const FaceIter &other) const {
+          return !(*this < other);
+        }
+
+        face_type operator*() const {
+          return obj->meshes[mesh]->faces[face];
+        }
+      };
+
+      typedef FaceIter<const face_t *> const_face_iter;
+      typedef FaceIter<face_t *> face_iter;
+
+      face_iter faceBegin() { return face_iter(this, 0, 0); }
+      face_iter faceEnd() { return face_iter(this, meshes.size(), 0); }
+
+      const_face_iter faceBegin() const { return const_face_iter(this, 0, 0); }
+      const_face_iter faceEnd() const { return const_face_iter(this, meshes.size(), 0); }
+
+      aabb_t getAABB() const {
+        return aabb_t(meshes.begin(), meshes.end());
+      }
+
+      template<typename func_t>
+      void transform(func_t func) {
+        for (size_t i = 0; i < vertex_storage.size(); ++i) {
+          vertex_storage[i].v = func(vertex_storage[i].v);
+        }
+        for (size_t i = 0; i < meshes.size(); ++i) {
+          meshes[i]->recalc();
+        }
+      }
+
+      MeshSet(const std::vector<typename vertex_t::vector_t> &points,
+              size_t n_faces,
+              const std::vector<int> &face_indices);
+
+      // Construct a mesh set from a set of disconnected faces. Takes
+      // posession of the face pointers.
+      MeshSet(std::vector<face_t *> &faces);
+
+      MeshSet(std::list<face_t *> &faces);
+
+      MeshSet(std::vector<vertex_t> &_vertex_storage,
+              std::vector<mesh_t *> &_meshes);
+
+      // This constructor consolidates and rewrites vertex pointers in
+      // each mesh, repointing them to local storage.
+      MeshSet(std::vector<mesh_t *> &_meshes);
+
+      MeshSet *clone() const;
+
+      ~MeshSet();
+
+      bool isClosed() const {
+        for (size_t i = 0; i < meshes.size(); ++i) {
+          if (!meshes[i]->isClosed()) return false;
+        }
+        return true;
+      }
+
+
+      void invert() {
+        for (size_t i = 0; i < meshes.size(); ++i) {
+          meshes[i]->invert();
+        }
+      }
+
+      void collectVertices();
+
+      void canonicalize();
+    };
+
+
+
+    carve::PointClass classifyPoint(
+        const carve::mesh::MeshSet<3> *meshset,
+        const carve::geom::RTreeNode<3, carve::mesh::Face<3> *> *face_rtree,
+        const carve::geom::vector<3> &v,
+        bool even_odd = false,
+        const carve::mesh::Mesh<3> *mesh = NULL,
+        const carve::mesh::Face<3> **hit_face = NULL);
+
+
+
+  }
+
+
+
+  mesh::MeshSet<3> *meshFromPolyhedron(const poly::Polyhedron *, int manifold_id);
+  poly::Polyhedron *polyhedronFromMesh(const mesh::MeshSet<3> *, int manifold_id);
+
+
+
+};
+
+#include <carve/mesh_impl.hpp>
diff --git a/extern/carve/include/carve/mesh_impl.hpp b/extern/carve/include/carve/mesh_impl.hpp
new file mode 100644
index 00000000000..23b0a436573
--- /dev/null
+++ b/extern/carve/include/carve/mesh_impl.hpp
@@ -0,0 +1,1015 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/geom2d.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/djset.hpp>
+
+#include <iostream>
+#include <deque>
+
+#include <stddef.h>
+
+namespace carve {
+  namespace mesh {
+
+
+
+    namespace detail {
+      template<typename list_t>
+      struct list_iter_t {
+        typedef std::bidirectional_iterator_tag iterator_category;
+        typedef list_t                          value_type;
+        typedef ptrdiff_t                       difference_type;
+        typedef value_type &                    reference;
+        typedef value_type *                    pointer;
+
+        list_t *curr;
+        int pos;
+
+        list_iter_t() { }
+        list_iter_t(list_t *_curr, int _pos) : curr(_curr), pos(_pos) { }
+
+        list_iter_t operator++(int) { list_iter_t result(*this); ++pos; curr = curr->next; return result; }
+        list_iter_t operator--(int) { list_iter_t result(*this); --pos; curr = curr->prev; return result; }
+
+        list_iter_t operator++() { ++pos; curr = curr->next; return *this; }
+        list_iter_t operator--() { --pos; curr = curr->prev; return *this; }
+
+        bool operator==(const list_iter_t &other) const { return curr == other.curr && pos == other.pos; }
+        bool operator!=(const list_iter_t &other) const { return curr != other.curr || pos != other.pos; }
+
+        reference operator*() { return *curr; }
+        pointer operator->() { return curr; }
+
+        int idx() const { return pos; }
+      };
+    }
+
+
+
+    template<unsigned ndim>
+    Edge<ndim> *Edge<ndim>::mergeFaces() {
+      if (rev == NULL) return NULL;
+
+      face_t *fwdface = face;
+      face_t *revface = rev->face;
+
+      size_t n_removed = 0;
+
+      Edge *splice_beg = this;
+      do {
+        splice_beg = splice_beg->prev;
+        ++n_removed;
+      } while (splice_beg != this &&
+               splice_beg->rev &&
+               splice_beg->next->rev->prev == splice_beg->rev);
+
+      if (splice_beg == this) {
+        // edge loops are completely matched.
+        return NULL;
+      }
+
+      Edge *splice_end = this;
+      do {
+        splice_end = splice_end->next;
+        ++n_removed;
+      } while (splice_end->rev &&
+               splice_end->prev->rev->next == splice_end->rev);
+
+      --n_removed;
+
+      Edge *link1_p = splice_beg;
+      Edge *link1_n = splice_beg->next->rev->next;
+
+      Edge *link2_p = splice_end->prev->rev->prev;
+      Edge *link2_n = splice_end;
+
+      CARVE_ASSERT(link1_p->face == fwdface);
+      CARVE_ASSERT(link1_n->face == revface);
+
+      CARVE_ASSERT(link2_p->face == revface);
+      CARVE_ASSERT(link2_n->face == fwdface);
+
+      Edge *left_loop = link1_p->next;
+
+      CARVE_ASSERT(left_loop->rev == link1_n->prev);
+
+      _link(link2_n->prev, link1_p->next);
+      _link(link1_n->prev, link2_p->next);
+
+      _link(link1_p, link1_n);
+      _link(link2_p, link2_n);
+
+      fwdface->edge = link1_p;
+
+      for (Edge *e = link1_n; e != link2_n; e = e->next) {
+        CARVE_ASSERT(e->face == revface);
+        e->face = fwdface;
+        fwdface->n_edges++;
+      }
+      for (Edge *e = link2_n; e != link1_n; e = e->next) {
+        CARVE_ASSERT(e->face == fwdface);
+      }
+
+      fwdface->n_edges -= n_removed;
+
+      revface->n_edges = 0;
+      revface->edge = NULL;
+
+      _setloopface(left_loop, NULL);
+      _setloopface(left_loop->rev, NULL);
+
+      return left_loop;
+    }
+
+
+
+    template<unsigned ndim>
+    Edge<ndim> *Edge<ndim>::removeHalfEdge() {
+      Edge *n = NULL;
+      if (face) {
+        face->n_edges--;
+      }
+
+      if (next == this) {
+        if (face) face->edge = NULL;
+      } else {
+        if (face && face->edge == this) face->edge = next;
+        next->prev = prev;
+        prev->next = next;
+        n = next;
+      }
+      delete this;
+      return n;
+    }
+
+
+
+    template<unsigned ndim>
+    Edge<ndim> *Edge<ndim>::removeEdge() {
+      if (rev) {
+        rev->removeHalfEdge();
+      }
+      return removeHalfEdge();
+    }
+
+
+
+    template<unsigned ndim>
+    void Edge<ndim>::unlink() {
+      if (rev) { rev->rev = NULL; rev = NULL; }
+      if (prev->rev) { prev->rev->rev = NULL; prev->rev = NULL; }
+
+      if (face) {
+        face->n_edges--;
+        if (face->edge == this) face->edge = next;
+        face = NULL;
+      }
+
+      next->prev = prev;
+      prev->next = next;
+
+      prev = next = this;
+    }
+
+
+
+    template<unsigned ndim>
+    void Edge<ndim>::insertBefore(Edge<ndim> *other) {
+      if (prev != this) unlink();
+      prev = other->prev;
+      next = other;
+      next->prev = this;
+      prev->next = this;
+
+      if (prev->rev) { prev->rev->rev = NULL;  prev->rev = NULL; }
+    }
+
+
+
+    template<unsigned ndim>
+    void Edge<ndim>::insertAfter(Edge<ndim> *other) {
+      if (prev != this) unlink();
+      next = other->next;
+      prev = other;
+      next->prev = this;
+      prev->next = this;
+
+      if (prev->rev) { prev->rev->rev = NULL;  prev->rev = NULL; }
+    }
+
+
+
+    template<unsigned ndim>
+    size_t Edge<ndim>::loopSize() const {
+      const Edge *e = this;
+      size_t n = 0;
+      do { e = e->next; ++n; } while (e != this);
+      return n;
+    }
+
+
+
+    template<unsigned ndim>
+    Edge<ndim> *Edge<ndim>::perimNext() const {
+      if (rev) return NULL;
+      Edge *e = next;
+      while(e->rev) {
+        e = e->rev->next;
+      }
+      return e;
+    }
+
+
+
+    template<unsigned ndim>
+    Edge<ndim> *Edge<ndim>::perimPrev() const {
+      if (rev) return NULL;
+      Edge *e = prev;
+      while(e->rev) {
+        e = e->rev->prev;
+      }
+      return e;
+    }
+
+
+
+    template<unsigned ndim>
+    Edge<ndim>::Edge(vertex_t *_vert, face_t *_face) :
+        vert(_vert), face(_face), prev(NULL), next(NULL), rev(NULL) {
+      prev = next = this;
+    }
+
+
+
+    template<unsigned ndim>
+    Edge<ndim>::~Edge() {
+    }
+
+
+
+    template<unsigned ndim>
+    typename Face<ndim>::aabb_t Face<ndim>::getAABB() const {
+      aabb_t aabb;
+      aabb.fit(begin(), end(), vector_mapping());
+      return aabb;
+    }
+
+
+
+    template<unsigned ndim>
+    bool Face<ndim>::recalc() {
+      if (!carve::geom3d::fitPlane(begin(), end(), vector_mapping(), plane)) {
+        return false;
+      }
+
+      int da = carve::geom::largestAxis(plane.N);
+      double A = carve::geom2d::signedArea(begin(), end(), projection_mapping(getProjector(false, da)));
+
+      if ((A < 0.0) ^ (plane.N.v[da] < 0.0)) {
+        plane.negate();
+      }
+
+      project = getProjector(plane.N.v[da] > 0, da);
+      unproject = getUnprojector(plane.N.v[da] > 0, da);
+
+      return true;
+    }
+
+
+
+    template<unsigned ndim>
+    void Face<ndim>::clearEdges() {
+      if (!edge) return;
+
+      edge_t *curr = edge;
+      do {
+        edge_t *next = curr->next;
+        delete curr;
+        curr = next;
+      } while (curr != edge);
+
+      edge = NULL;
+
+      n_edges = 0;
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void Face<ndim>::loopFwd(iter_t begin, iter_t end) {
+      clearEdges();
+      if (begin == end) return;
+      edge = new edge_t(*begin, this); ++n_edges; ++begin;
+      while (begin != end) {
+        edge_t *e = new edge_t(*begin, this);
+        e->insertAfter(edge->prev);
+        ++n_edges;
+        ++begin;
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void Face<ndim>::loopRev(iter_t begin, iter_t end) {
+      clearEdges();
+      if (begin == end) return;
+      edge = new edge_t(*begin, this); ++n_edges; ++begin;
+      while (begin != end) {
+        edge_t *e = new edge_t(*begin, this);
+        e->insertBefore(edge->next);
+        ++n_edges;
+        ++begin;
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void Face<ndim>::init(iter_t begin, iter_t end) {
+      loopFwd(begin, end);
+    }
+
+
+
+    template<unsigned ndim>
+    void Face<ndim>::init(vertex_t *a, vertex_t *b, vertex_t *c) {
+      clearEdges();
+      edge_t *ea = new edge_t(a, this);
+      edge_t *eb = new edge_t(b, this);
+      edge_t *ec = new edge_t(c, this);
+      eb->insertAfter(ea);
+      ec->insertAfter(eb);
+      edge = ea;
+      n_edges = 3;
+    }
+
+
+
+    template<unsigned ndim>
+    void Face<ndim>::init(vertex_t *a, vertex_t *b, vertex_t *c, vertex_t *d) {
+      clearEdges();
+      edge_t *ea = new edge_t(a, this);
+      edge_t *eb = new edge_t(b, this);
+      edge_t *ec = new edge_t(c, this);
+      edge_t *ed = new edge_t(d, this);
+      eb->insertAfter(ea);
+      ec->insertAfter(eb);
+      ed->insertAfter(ec);
+      edge = ea;
+      n_edges = 4;
+    }
+
+
+
+    template<unsigned ndim>
+    void Face<ndim>::getVertices(std::vector<vertex_t *> &verts) const {
+      verts.clear();
+      verts.reserve(n_edges);
+      const edge_t *e = edge;
+      do { verts.push_back(e->vert); e = e->next; } while (e != edge);
+    }
+
+
+
+    template<unsigned ndim>
+    void Face<ndim>::getProjectedVertices(std::vector<carve::geom::vector<2> > &verts) const {
+      verts.clear();
+      verts.reserve(n_edges);
+      const edge_t *e = edge;
+      do { verts.push_back(project(e->vert->v)); e = e->next; } while (e != edge);
+    }
+
+
+
+    template<unsigned ndim>
+    typename Face<ndim>::vector_t Face<ndim>::centroid() const {
+      vector_t v;
+      edge_t *e = edge;
+      do {
+        v += e->vert->v;
+        e = e->next;
+      } while(e != edge);
+      v /= n_edges;
+      return v;
+    }
+
+
+
+    template<unsigned ndim>
+    void Face<ndim>::canonicalize() {
+      edge_t *min = edge;
+      edge_t *e = edge;
+
+      do {
+        if (e->vert < min->vert) min = e;
+        e = e->next;
+      } while (e != edge);
+
+      edge = min;
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    Face<ndim> *Face<ndim>::create(iter_t beg, iter_t end, bool reversed) const {
+      Face *r = new Face();
+
+      if (reversed) {
+        r->loopRev(beg, end);
+        r->plane = -plane;
+      } else {
+        r->loopFwd(beg, end);
+        r->plane = plane;
+      }
+
+      int da = carve::geom::largestAxis(r->plane.N);
+
+      r->project = r->getProjector(r->plane.N.v[da] > 0, da);
+      r->unproject = r->getUnprojector(r->plane.N.v[da] > 0, da);
+
+      return r;
+    }
+
+
+
+    template<unsigned ndim>
+    Face<ndim> *Face<ndim>::clone(const vertex_t *old_base,
+                                  vertex_t *new_base,
+                                  std::unordered_map<const edge_t *, edge_t *> &edge_map) const {
+      Face *r = new Face(*this);
+
+      edge_t *e = edge;
+      edge_t *r_p = NULL;
+      edge_t *r_e;
+      do {
+        r_e = new edge_t(e->vert - old_base + new_base, r);
+        edge_map[e] = r_e;
+        if (r_p) {
+          r_p->next = r_e;
+          r_e->prev = r_p;
+        } else {
+          r->edge = r_e;
+        }
+        r_p = r_e;
+
+        if (e->rev) {
+          typename std::unordered_map<const edge_t *, edge_t *>::iterator rev_i = edge_map.find(e->rev);
+          if (rev_i != edge_map.end()) {
+            r_e->rev = (*rev_i).second;
+            (*rev_i).second->rev = r_e;
+          }
+        }
+
+        e = e->next;
+      } while (e != edge);
+      r_e->next = r->edge;
+      r->edge->prev = r_e;
+      return r;
+    }
+
+
+
+    template<unsigned ndim>
+    Mesh<ndim>::Mesh(std::vector<face_t *> &_faces,
+                     std::vector<edge_t *> &_open_edges,
+                     std::vector<edge_t *> &_closed_edges,
+                     bool _is_negative) {
+      std::swap(faces, _faces);
+      std::swap(open_edges, _open_edges);
+      std::swap(closed_edges, _closed_edges);
+      is_negative = _is_negative;
+      meshset = NULL;
+
+      for (size_t i = 0; i < faces.size(); ++i) {
+        faces[i]->mesh = this;
+      }
+    }
+
+
+
+    namespace detail {
+      template<typename iter_t>
+      void FaceStitcher::initEdges(iter_t begin,
+                                   iter_t end) {
+        size_t c = 0;
+        for (iter_t i = begin; i != end; ++i) {
+          face_t *face = *i;
+          CARVE_ASSERT(face->mesh == NULL); // for the moment, can only insert a face into a mesh once.
+
+          face->id = c++;
+          edge_t *e = face->edge;
+          do {
+            edges[vpair_t(e->v1(), e->v2())].push_back(e);
+            e = e->next;
+            if (e->rev) { e->rev->rev = NULL; e->rev = NULL; }
+          } while (e != face->edge);
+        }
+        face_groups.init(c);
+        is_open.clear();
+        is_open.resize(c, false);
+      }
+
+      template<typename iter_t>
+      void FaceStitcher::build(iter_t begin,
+                               iter_t end,
+                               std::vector<Mesh<3> *> &meshes) {
+        // work out what set each face belongs to, and then construct
+        // mesh instances for each set of faces.
+        std::vector<size_t> index_set;
+        std::vector<size_t> set_size;
+        face_groups.get_index_to_set(index_set, set_size);
+
+        std::vector<std::vector<face_t *> > mesh_faces;
+        mesh_faces.resize(set_size.size());
+        for (size_t i = 0; i < set_size.size(); ++i) {
+          mesh_faces[i].reserve(set_size[i]);
+        }
+      
+        for (iter_t i = begin; i != end; ++i) {
+          face_t *face = *i;
+          mesh_faces[index_set[face->id]].push_back(face);
+        }
+
+        meshes.clear();
+        meshes.reserve(mesh_faces.size());
+        for (size_t i = 0; i < mesh_faces.size(); ++i) {
+          meshes.push_back(new Mesh<3>(mesh_faces[i]));
+        }
+      }
+
+      template<typename iter_t>
+      void FaceStitcher::create(iter_t begin,
+                                iter_t end,
+                                std::vector<Mesh<3> *> &meshes) {
+        initEdges(begin, end);
+        construct();
+        build(begin, end, meshes);
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    void Mesh<ndim>::cacheEdges() {
+      closed_edges.clear();
+      open_edges.clear();
+
+      for (size_t i = 0; i < faces.size(); ++i) {
+        face_t *face = faces[i];
+        edge_t *e = face->edge;
+        do {
+          if (e->rev == NULL) {
+            open_edges.push_back(e);
+          } else if (e < e->rev) {
+            closed_edges.push_back(e);
+          }
+          e = e->next;
+        } while (e != face->edge);
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    Mesh<ndim>::Mesh(std::vector<face_t *> &_faces) : faces(), open_edges(), closed_edges(), meshset(NULL) {
+      faces.swap(_faces);
+      for (size_t i = 0; i < faces.size(); ++i) {
+        faces[i]->mesh = this;
+      }
+      cacheEdges();
+      calcOrientation();
+    }
+
+
+
+    template<unsigned ndim>
+    void Mesh<ndim>::calcOrientation() {
+      if (open_edges.size() || !closed_edges.size()) {
+        is_negative = false;
+      } else {
+        edge_t *emin = closed_edges[0];
+        if (emin->rev->v1()->v < emin->v1()->v) emin = emin->rev;
+        for (size_t i = 1; i < closed_edges.size(); ++i) {
+          if (closed_edges[i]->v1()->v      < emin->v1()->v) emin = closed_edges[i];
+          if (closed_edges[i]->rev->v1()->v < emin->v1()->v) emin = closed_edges[i]->rev;
+        }
+
+        std::vector<face_t *> min_faces;
+        edge_t *e = emin;
+        do {
+          min_faces.push_back(e->face);
+          CARVE_ASSERT(e->rev != NULL);
+          e = e->rev->next;
+          CARVE_ASSERT(e->v1() == emin->v1());
+          CARVE_ASSERT(e->v1()->v < e->v2()->v);
+          CARVE_ASSERT(e->v1()->v.x <= e->v2()->v.x);
+        } while (e != emin);
+
+        double max_abs_x = 0.0;
+        for (size_t f = 0; f < min_faces.size(); ++f) {
+          if (fabs(min_faces[f]->plane.N.x) > fabs(max_abs_x)) max_abs_x = min_faces[f]->plane.N.x;
+        }
+        is_negative =  max_abs_x > 0.0;
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    Mesh<ndim> *Mesh<ndim>::clone(const vertex_t *old_base,
+                                  vertex_t *new_base) const {
+      std::vector<face_t *> r_faces;
+      std::vector<edge_t *> r_open_edges;
+      std::vector<edge_t *> r_closed_edges;
+      std::unordered_map<const edge_t *, edge_t *> edge_map;
+
+      r_faces.reserve(faces.size());
+      r_open_edges.reserve(r_open_edges.size());
+      r_closed_edges.reserve(r_closed_edges.size());
+
+      for (size_t i = 0; i < faces.size(); ++i) {
+        r_faces.push_back(faces[i]->clone(old_base, new_base, edge_map));
+      }
+      for (size_t i = 0; i < closed_edges.size(); ++i) {
+        r_closed_edges.push_back(edge_map[closed_edges[i]]);
+        r_closed_edges.back()->rev = edge_map[closed_edges[i]->rev];
+      }
+      for (size_t i = 0; i < open_edges.size(); ++i) {
+        r_open_edges.push_back(edge_map[open_edges[i]]);
+      }
+
+      return new Mesh(r_faces, r_open_edges, r_closed_edges, is_negative);
+    }
+
+
+
+    template<unsigned ndim>
+    Mesh<ndim>::~Mesh() {
+      for (size_t i = 0; i < faces.size(); ++i) {
+        delete faces[i];
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void Mesh<ndim>::create(iter_t begin, iter_t end, std::vector<Mesh<ndim> *> &meshes) {
+      meshes.clear();
+    }
+
+
+
+    template<>
+    template<typename iter_t>
+    void Mesh<3>::create(iter_t begin, iter_t end, std::vector<Mesh<3> *> &meshes) {
+      detail::FaceStitcher().create(begin, end, meshes);
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename iter_t>
+    void MeshSet<ndim>::_init_from_faces(iter_t begin, iter_t end) {
+      typedef std::unordered_map<const vertex_t *, size_t> map_t;
+      map_t vmap;
+
+      for (iter_t i = begin; i != end; ++i) {
+        face_t *f = *i;
+        edge_t *e = f->edge;
+        do {
+          typename map_t::const_iterator j = vmap.find(e->vert);
+          if (j == vmap.end()) {
+            size_t idx = vmap.size();
+            vmap[e->vert] = idx;
+          }
+          e = e->next;
+        } while (e != f->edge);
+      }
+
+      vertex_storage.resize(vmap.size());
+      for (typename map_t::const_iterator i = vmap.begin(); i != vmap.end(); ++i) {
+        vertex_storage[(*i).second].v = (*i).first->v;
+      }
+
+      for (iter_t i = begin; i != end; ++i) {
+        face_t *f = *i;
+        edge_t *e = f->edge;
+        do {
+          e->vert = &vertex_storage[vmap[e->vert]];
+          e = e->next;
+        } while (e != f->edge);
+      }
+
+      mesh_t::create(begin, end, meshes);
+
+      for (size_t i = 0; i < meshes.size(); ++i) {
+        meshes[i]->meshset = this;
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    MeshSet<ndim>::MeshSet(const std::vector<typename MeshSet<ndim>::vertex_t::vector_t> &points,
+                           size_t n_faces,
+                           const std::vector<int> &face_indices) {
+      vertex_storage.reserve(points.size());
+      std::vector<face_t *> faces;
+      faces.reserve(n_faces);
+      for (size_t i = 0; i < points.size(); ++i) {
+        vertex_storage.push_back(vertex_t(points[i]));
+      }
+
+      std::vector<vertex_t *> v;
+      size_t p = 0;
+      for (size_t i = 0; i < n_faces; ++i) {
+        const size_t N = face_indices[p++];
+        v.clear();
+        v.reserve(N);
+        for (size_t j = 0; j < N; ++j) {
+          v.push_back(&vertex_storage[face_indices[p++]]);
+        }
+        faces.push_back(new face_t(v.begin(), v.end()));
+      }
+      CARVE_ASSERT(p == face_indices.size());
+      mesh_t::create(faces.begin(), faces.end(), meshes);
+
+      for (size_t i = 0; i < meshes.size(); ++i) {
+        meshes[i]->meshset = this;
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    MeshSet<ndim>::MeshSet(std::vector<face_t *> &faces) {
+      _init_from_faces(faces.begin(), faces.end());
+    }
+
+
+
+    template<unsigned ndim>
+    MeshSet<ndim>::MeshSet(std::list<face_t *> &faces) {
+      _init_from_faces(faces.begin(), faces.end());
+    }
+
+
+
+    template<unsigned ndim>
+    MeshSet<ndim>::MeshSet(std::vector<vertex_t> &_vertex_storage,
+                           std::vector<mesh_t *> &_meshes) {
+      vertex_storage.swap(_vertex_storage);
+      meshes.swap(_meshes);
+
+      for (size_t i = 0; i < meshes.size(); ++i) {
+        meshes[i]->meshset = this;
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    MeshSet<ndim>::MeshSet(std::vector<typename MeshSet<ndim>::mesh_t *> &_meshes) {
+      meshes.swap(_meshes);
+      std::unordered_map<vertex_t *, size_t> vert_idx;
+
+      for (size_t m = 0; m < meshes.size(); ++m) {
+        mesh_t *mesh = meshes[m];
+        CARVE_ASSERT(mesh->meshset == NULL);
+        mesh->meshset = this;
+        for (size_t f = 0; f < mesh->faces.size(); ++f) {
+          face_t *face = mesh->faces[f];
+          edge_t *edge = face->edge;
+          do {
+            vert_idx[edge->vert] = 0;
+            edge = edge->next;
+          } while (edge != face->edge);
+        }
+      }
+
+      vertex_storage.reserve(vert_idx.size());
+      for (typename std::unordered_map<vertex_t *, size_t>::iterator i = vert_idx.begin(); i != vert_idx.end(); ++i) {
+        (*i).second = vertex_storage.size();
+        vertex_storage.push_back(*(*i).first);
+      }
+
+      for (size_t m = 0; m < meshes.size(); ++m) {
+        mesh_t *mesh = meshes[m];
+        for (size_t f = 0; f < mesh->faces.size(); ++f) {
+          face_t *face = mesh->faces[f];
+          edge_t *edge = face->edge;
+          do {
+            size_t i = vert_idx[edge->vert];
+            edge->vert = &vertex_storage[i];
+            edge = edge->next;
+          } while (edge != face->edge);
+        }
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    MeshSet<ndim> *MeshSet<ndim>::clone() const {
+      std::vector<vertex_t> r_vertex_storage = vertex_storage;
+      std::vector<mesh_t *> r_meshes;
+      for (size_t i = 0; i < meshes.size(); ++i) {
+        r_meshes.push_back(meshes[i]->clone(&vertex_storage[0], &r_vertex_storage[0]));
+      }
+
+      return new MeshSet(r_vertex_storage, r_meshes);
+    }
+
+
+
+    template<unsigned ndim>
+    MeshSet<ndim>::~MeshSet() {
+      for (size_t i = 0; i < meshes.size(); ++i) {
+        delete meshes[i];
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename face_type>
+    MeshSet<ndim>::FaceIter<face_type>::FaceIter(const MeshSet<ndim> *_obj, size_t _mesh, size_t _face) : obj(_obj), mesh(_mesh), face(_face) {
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename face_type>
+    void MeshSet<ndim>::FaceIter<face_type>::fwd(size_t n) {
+      if (mesh < obj->meshes.size()) {
+        face += n;
+        while (face >= obj->meshes[mesh]->faces.size()) {
+          face -= obj->meshes[mesh++]->faces.size();
+          if (mesh == obj->meshes.size()) { face = 0; break; }
+        }
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename face_type>
+    void MeshSet<ndim>::FaceIter<face_type>::rev(size_t n) {
+      while (n > face) {
+        n -= face;
+        if (mesh == 0) { face = 0; return; }
+        face = obj->meshes[--mesh]->faces.size() - 1;
+      }
+      face -= n;
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename face_type>
+    void MeshSet<ndim>::FaceIter<face_type>::adv(int n) {
+      if (n > 0) {
+        fwd((size_t)n);
+      } else if (n < 0) {
+        rev((size_t)-n);
+      }
+    }
+
+
+
+    template<unsigned ndim>
+    template<typename face_type>
+    typename MeshSet<ndim>::template FaceIter<face_type>::difference_type
+    MeshSet<ndim>::FaceIter<face_type>::operator-(const FaceIter &other) const {
+      CARVE_ASSERT(obj == other.obj);
+      if (mesh == other.mesh) return face - other.face;
+
+      size_t m = 0;
+      for (size_t i = std::min(mesh, other.mesh) + 1; i < std::max(mesh, other.mesh); ++i) {
+        m += obj->meshes[i]->faces.size();
+      }
+
+      if (mesh < other.mesh) {
+        return -(difference_type)((obj->meshes[mesh]->faces.size() - face) + m + other.face);
+      } else {
+        return +(difference_type)((obj->meshes[other.mesh]->faces.size() - other.face) + m + face);
+      }
+    }
+
+
+
+    template<typename order_t>
+    struct VPtrSort {
+      order_t order;
+
+      VPtrSort(const order_t &_order = order_t()) : order(_order) {}
+
+      template<unsigned ndim>
+      bool operator()(carve::mesh::Vertex<ndim> *a,
+                      carve::mesh::Vertex<ndim> *b) const {
+        return order(a->v, b->v);
+      }
+    };
+
+
+
+    template<unsigned ndim>
+    void MeshSet<ndim>::collectVertices() {
+      std::unordered_map<vertex_t *, size_t> vert_idx;
+
+      for (size_t m = 0; m < meshes.size(); ++m) {
+        mesh_t *mesh = meshes[m];
+
+        for (size_t f = 0; f < mesh->faces.size(); ++f) {
+          face_t *face = mesh->faces[f];
+          edge_t *edge = face->edge;
+          do {
+            vert_idx[edge->vert] = 0;
+            edge = edge->next;
+          } while (edge != face->edge);
+        }
+      }
+
+      std::vector<vertex_t> new_vertex_storage;
+      new_vertex_storage.reserve(vert_idx.size());
+      for (typename std::unordered_map<vertex_t *, size_t>::iterator
+             i = vert_idx.begin(); i != vert_idx.end(); ++i) {
+        (*i).second = new_vertex_storage.size();
+        new_vertex_storage.push_back(*(*i).first);
+      }
+
+      for (size_t m = 0; m < meshes.size(); ++m) {
+        mesh_t *mesh = meshes[m];
+        for (size_t f = 0; f < mesh->faces.size(); ++f) {
+          face_t *face = mesh->faces[f];
+          edge_t *edge = face->edge;
+          do {
+            size_t i = vert_idx[edge->vert];
+            edge->vert = &new_vertex_storage[i];
+            edge = edge->next;
+          } while (edge != face->edge);
+        }
+      }
+
+      std::swap(vertex_storage, new_vertex_storage);
+    }
+
+
+
+    template<unsigned ndim>
+    void MeshSet<ndim>::canonicalize() {
+      std::vector<vertex_t *> vptr;
+      std::vector<vertex_t *> vmap;
+      std::vector<vertex_t> vout;
+      const size_t N = vertex_storage.size();
+
+      vptr.reserve(N);
+      vout.reserve(N);
+      vmap.resize(N);
+
+      for (size_t i = 0; i != N; ++i) {
+        vptr.push_back(&vertex_storage[i]);
+      }
+      std::sort(vptr.begin(), vptr.end(), VPtrSort<std::less<typename vertex_t::vector_t> >());
+
+      for (size_t i = 0; i != N; ++i) {
+        vout.push_back(*vptr[i]);
+        vmap[vptr[i] - &vertex_storage[0]] = &vout[i];
+      }
+
+      for (face_iter i = faceBegin(); i != faceEnd(); ++i) {
+        for (typename face_t::edge_iter_t j = (*i)->begin(); j != (*i)->end(); ++j) {
+          (*j).vert = vmap[(*j).vert - &vertex_storage[0]];
+        }
+        (*i)->canonicalize();
+      }
+
+      vertex_storage.swap(vout);
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/mesh_ops.hpp b/extern/carve/include/carve/mesh_ops.hpp
new file mode 100644
index 00000000000..02b1bde4e45
--- /dev/null
+++ b/extern/carve/include/carve/mesh_ops.hpp
@@ -0,0 +1,975 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/mesh.hpp>
+
+#include <iostream>
+#include <fstream>
+
+namespace carve {
+  namespace mesh {
+    namespace detail {
+      // make a triangle out of three edges.
+      template<unsigned ndim>
+      void link(Edge<ndim> *e1, Edge<ndim> *e2, Edge<ndim> *e3, Face<ndim> *f = NULL) {
+        e1->next = e2; e2->next = e3; e3->next = e1;
+        e3->prev = e2; e2->prev = e1; e1->prev = e3;
+        e1->face = e2->face = e3->face = f;
+        if (f) {
+          f->edge = e1;
+          f->recalc();
+        }
+      }
+
+
+
+      template<unsigned ndim, typename proj_t>
+      double loopArea(carve::mesh::Edge<ndim> *edge, proj_t proj) {
+        double A = 0.0;
+        carve::mesh::Edge<3> *e = edge;
+        do {
+          carve::geom2d::P2 p1 = proj(e->vert->v);
+          carve::geom2d::P2 p2 = proj(e->next->vert->v);
+          A += (p2.y + p1.y) * (p2.x - p1.x);
+          e = e->next;
+        } while (e != edge);
+        return A / 2.0;
+      }
+
+
+      
+      template<unsigned ndim, typename proj_t>
+      struct TriangulationData {
+        typedef Edge<ndim> edge_t;
+
+        struct VertexInfo {
+          double score;
+          carve::geom2d::P2 p;
+          bool convex;
+          bool failed;
+          VertexInfo *next, *prev;
+          edge_t *edge;
+
+          VertexInfo(edge_t *_edge,
+                     const carve::geom2d::P2 &_p) :
+              score(0.0), p(_p), convex(false), failed(false), next(NULL), prev(NULL), edge(_edge) {
+          }
+
+          bool isCandidate() const {
+            return convex && !failed;
+          }
+
+          void fail() {
+            failed = true;
+          }
+
+          static bool isLeft(const VertexInfo *a, const VertexInfo *b, const geom2d::P2 &p) {
+            if (a < b) {
+              return carve::geom2d::orient2d(a->p, b->p, p) > 0.0;
+            } else {
+              return carve::geom2d::orient2d(b->p, a->p, p) < 0.0;
+            }
+          }
+
+          // is the ear prev->edge->next convex?
+          bool testForConvexVertex() const {
+            return isLeft(next, prev, p);
+          }
+
+          static double triScore(const geom2d::P2 &a, const geom2d::P2 &b, const geom2d::P2 &c) {
+            // score is in the range: [0, 1]
+            // equilateral triangles score 1
+            // sliver triangles score 0
+            double dab = (a - b).length();
+            double dbc = (b - c).length();
+            double dca = (c - a).length();
+
+            if (dab < 1e-10 || dbc < 1e-10 || dca < 1e-10) return 0.0;
+
+            return std::max(std::min((dab + dbc) / dca, std::min((dab + dca) / dbc, (dbc + dca) / dab)) - 1.0, 0.0);
+          }
+
+          // calculate a score for the ear edge.
+          double calcScore() const {
+            double this_tri = triScore(prev->p, p, next->p);
+            double next_tri = triScore(prev->p, next->p, next->next->p);
+            double prev_tri = triScore(prev->prev->p, prev->p, next->p);
+
+            return this_tri + std::max(next_tri, prev_tri) * .2;
+          }
+
+          void recompute() {
+            convex = testForConvexVertex();
+            failed = false;
+            if (convex) {
+              score = calcScore();
+            } else {
+              score = -1e-5;
+            }
+          }
+
+          static bool inTriangle(const VertexInfo *a,
+                                 const VertexInfo *b,
+                                 const VertexInfo *c,
+                                 const geom2d::P2 &e) {
+            return !isLeft(b, a, e) && !isLeft(c, b, e) && !isLeft(a, c, e);
+          }
+
+
+          bool isClipable() const {
+            for (const VertexInfo *v_test = next->next; v_test != prev; v_test = v_test->next) {
+              if (v_test->convex) {
+                continue;
+              }
+
+              if (v_test->p == prev->p || v_test->p == next->p) {
+                continue;
+              }
+
+              if (v_test->p == p) {
+                if (v_test->next->p == prev->p && v_test->prev->p == next->p) {
+                  return false;
+                }
+              
+                if (v_test->next->p == prev->p || v_test->prev->p == next->p) {
+                  continue;
+                }
+              }
+
+              if (inTriangle(prev, this, next, v_test->p)) {
+                return false;
+              }
+            }
+            return true;
+          }
+        };
+
+        struct order_by_score {
+          bool operator()(const VertexInfo *a, const VertexInfo *b) const {
+            return a->score < b->score;
+          }
+        };
+
+        typedef std::pair<VertexInfo *, VertexInfo *> diag_t;
+
+        proj_t proj;
+
+        geom2d::P2 P(const VertexInfo *vi) const {
+          return vi->p;
+        }
+
+        geom2d::P2 P(const edge_t *edge) const {
+          return proj(edge->vert->v);
+        }
+
+        bool isLeft(const edge_t *a, const edge_t *b, const geom2d::P2 &p) const {
+          if (a < b) {
+            return carve::geom2d::orient2d(P(a), P(b), p) > 0.0;
+          } else {
+            return carve::geom2d::orient2d(P(b), P(a), p) < 0.0;
+          }
+        }
+
+        bool testForConvexVertex(const edge_t *vert) const {
+          return isLeft(vert->next, vert->prev, P(vert));
+        }
+
+        bool inCone(const VertexInfo *vert, const geom2d::P2 &p) const {
+          return geom2d::internalToAngle(P(vert->next), P(vert), P(vert->prev), p);
+        }
+
+        int windingNumber(VertexInfo *vert, const carve::geom2d::P2 &point) const {
+          int wn = 0;
+
+          VertexInfo *v = vert;
+          geom2d::P2 v_p = P(vert);
+          do {
+            geom2d::P2 n_p = P(v->next);
+            
+            if (v_p.y <= point.y) {
+              if (n_p.y > point.y && carve::geom2d::orient2d(v_p, n_p, point) > 0.0) {
+                ++wn;
+              }
+            } else {
+              if (n_p.y <= point.y && carve::geom2d::orient2d(v_p, n_p, point) < 0.0) {
+                --wn;
+              }
+            }
+            v = v->next;
+            v_p = n_p;
+          } while (v != vert);
+
+          return wn;
+        }
+
+        bool diagonalIsCandidate(diag_t diag) const {
+          VertexInfo *v1 = diag.first;
+          VertexInfo *v2 = diag.second;
+          return (inCone(v1, P(v2)) && inCone(v2, P(v1)));
+        }
+
+        bool testDiagonal(diag_t diag) const {
+          // test whether v1-v2 is a valid diagonal.
+          VertexInfo *v1 = diag.first;
+          VertexInfo *v2 = diag.second;
+          geom2d::P2 v1p = P(v1);
+          geom2d::P2 v2p = P(v2);
+
+          bool intersected = false;
+
+          for (VertexInfo *t = v1->next; !intersected && t != v1->prev; t = t->next) {
+            VertexInfo *u = t->next;
+            if (t == v2 || u == v2) continue;
+
+            geom2d::P2 tp = P(t);
+            geom2d::P2 up = P(u);
+
+            double l_a1 = carve::geom2d::orient2d(v1p, v2p, tp);
+            double l_a2 = carve::geom2d::orient2d(v1p, v2p, up);
+
+            double l_b1 = carve::geom2d::orient2d(tp, up, v1p);
+            double l_b2 = carve::geom2d::orient2d(tp, up, v2p);
+
+            if (l_a1 > l_a2) std::swap(l_a1, l_a2);
+            if (l_b1 > l_b2) std::swap(l_b1, l_b2);
+
+            if (l_a1 == 0.0 && l_a2 == 0.0 &&
+                l_b1 == 0.0 && l_b2 == 0.0) {
+              // colinear
+              if (std::max(tp.x, up.x) >= std::min(v1p.x, v2p.x) && std::min(tp.x, up.x) <= std::max(v1p.x, v2p.x)) {
+                // colinear and intersecting
+                intersected = true;
+              }
+              continue;
+            }
+
+            if (l_a2 <= 0.0 || l_a1 >= 0.0  || l_b2 <= 0.0 || l_b1 >= 0.0) {
+              // no intersection
+              continue;
+            }
+
+            intersected = true;
+          }
+
+          if (!intersected) {
+            // test whether midpoint winding == 1
+
+            carve::geom2d::P2 mid = (v1p + v2p) / 2;
+            if (windingNumber(v1, mid) == 1) {
+              // this diagonal is ok
+              return true;
+            }
+          }
+          return false;
+        }
+
+        // Find the vertex half way around the loop (rounds upwards).
+        VertexInfo *findMidpoint(VertexInfo *vert) const {
+          VertexInfo *v = vert;
+          VertexInfo *r = vert;
+          while (1) {
+            r = r->next;
+            v = v->next; if (v == vert) return r;
+            v = v->next; if (v == vert) return r;
+          }
+        }
+
+        // Test all diagonals with a separation of a-b by walking both
+        // pointers around the loop. In the case where a-b divides the
+        // loop exactly in half, this will test each diagonal twice,
+        // but avoiding this case is not worth the extra effort
+        // required.
+        diag_t scanDiagonals(VertexInfo *a, VertexInfo *b) const {
+          VertexInfo *v1 = a;
+          VertexInfo *v2 = b;
+
+          do {
+            diag_t d(v1, v2);
+            if (diagonalIsCandidate(d) && testDiagonal(d)) {
+              return d;
+            }
+            v1 = v1->next;
+            v2 = v2->next;
+          } while (v1 != a);
+
+          return diag_t(NULL, NULL);
+        }
+
+        diag_t scanAllDiagonals(VertexInfo *a) const {
+          // Rationale: We want to find a diagonal that splits the
+          // loop into two as evenly as possible, to reduce the number
+          // of times that diagonal splitting is required. Start by
+          // scanning all diagonals separated by loop_len / 2, then
+          // decrease the separation until we find something.
+
+          // loops of length 2 or 3 have no possible diagonal.
+          if (a->next == a || a->next->next == a) return diag_t(NULL, NULL);
+
+          VertexInfo *b = findMidpoint(a);
+          while (b != a->next) {
+            diag_t d = scanDiagonals(a, b);
+            if (d != diag_t(NULL, NULL)) return d;
+            b = b->prev;
+          }
+
+          return diag_t(NULL, NULL);
+        }
+
+        diag_t findDiagonal(VertexInfo *vert) const {
+          return scanAllDiagonals(vert);
+        }
+
+        diag_t findHighScoringDiagonal(VertexInfo *vert) const {
+          typedef std::pair<double, diag_t> heap_entry_t;
+          VertexInfo *v1, *v2;
+          std::vector<heap_entry_t> heap;
+          size_t loop_len = 0;
+
+          v1 = vert;
+          do {
+            ++loop_len;
+            v1 = v1->next;
+          } while (v1 != vert);
+
+          v1 = vert;
+          do {
+            v2 = v1->next->next;
+            size_t dist = 2;
+            do {
+              if (diagonalIsCandidate(diag_t(v1, v2))) {
+                double score = std::min(dist, loop_len - dist);
+                // double score = (v1->edge->vert->v - v2->edge->vert->v).length2();
+                heap.push_back(heap_entry_t(score, diag_t(v1, v2)));
+              }
+              v2 = v2->next;
+              ++dist;
+            } while (v2 != vert && v2 != v1->prev);
+            v1 = v1->next;
+          } while (v1->next->next != vert);
+
+          std::make_heap(heap.begin(), heap.end());
+
+          while (heap.size()) {
+            std::pop_heap(heap.begin(), heap.end());
+            heap_entry_t h = heap.back();
+            heap.pop_back();
+
+            if (testDiagonal(h.second)) return h.second;
+          }
+
+          // couldn't find a diagonal that was ok.
+          return diag_t(NULL, NULL);
+        }
+
+        void splitEdgeLoop(VertexInfo *v1, VertexInfo *v2) {
+          VertexInfo *v1_copy = new VertexInfo(new Edge<ndim>(v1->edge->vert, NULL), v1->p);
+          VertexInfo *v2_copy = new VertexInfo(new Edge<ndim>(v2->edge->vert, NULL), v2->p);
+
+          v1_copy->edge->rev = v2_copy->edge;
+          v2_copy->edge->rev = v1_copy->edge;
+
+          v1_copy->edge->prev = v1->edge->prev;
+          v1_copy->edge->next = v2->edge;
+
+          v2_copy->edge->prev = v2->edge->prev;
+          v2_copy->edge->next = v1->edge;
+
+          v1->edge->prev->next = v1_copy->edge;
+          v1->edge->prev = v2_copy->edge;
+
+          v2->edge->prev->next = v2_copy->edge;
+          v2->edge->prev = v1_copy->edge;
+
+          v1_copy->prev = v1->prev;
+          v1_copy->next = v2;
+
+          v2_copy->prev = v2->prev;
+          v2_copy->next = v1;
+
+          v1->prev->next = v1_copy;
+          v1->prev = v2_copy;
+
+          v2->prev->next = v2_copy;
+          v2->prev = v1_copy;
+        }
+
+        VertexInfo *findDegenerateEar(VertexInfo *edge) {
+          VertexInfo *v = edge;
+
+          if (v->next == v || v->next->next == v) return NULL;
+
+          do {
+            if (P(v) == P(v->next)) {
+              return v;
+            } else if (P(v) == P(v->next->next)) {
+              if (P(v->next) == P(v->next->next->next)) {
+                // a 'z' in the loop: z (a) b a b c -> remove a-b-a -> z (a) a b c -> remove a-a-b (next loop) -> z a b c
+                // z --(a)-- b
+                //         /
+                //        /
+                //      a -- b -- d
+                return v->next;
+              } else {
+                // a 'shard' in the loop: z (a) b a c d -> remove a-b-a -> z (a) a b c d -> remove a-a-b (next loop) -> z a b c d
+                // z --(a)-- b
+                //         /
+                //        /
+                //      a -- c -- d
+                // n.b. can only do this if the shard is pointing out of the polygon. i.e. b is outside z-a-c
+                if (!carve::geom2d::internalToAngle(P(v->next->next->next), P(v), P(v->prev), P(v->next))) {
+                  return v->next;
+                }
+              }
+            }
+            v = v->next;
+          } while (v != edge);
+
+          return NULL;
+        }
+
+        // Clip off a vertex at vert, producing a triangle (with appropriate rev pointers)
+        template<typename out_iter_t>
+        VertexInfo *clipEar(VertexInfo *vert, out_iter_t out) {
+          CARVE_ASSERT(testForConvexVertex(vert->edge));
+
+          edge_t *p_edge = vert->edge->prev;
+          edge_t *n_edge = vert->edge->next;
+
+          edge_t *p_copy = new edge_t(p_edge->vert, NULL);
+          edge_t *n_copy = new edge_t(n_edge->vert, NULL);
+
+          n_copy->next = p_copy;
+          n_copy->prev = vert->edge;
+
+          p_copy->next = vert->edge;
+          p_copy->prev = n_copy;
+
+          vert->edge->next = n_copy;
+          vert->edge->prev = p_copy;
+
+          p_edge->next = n_edge;
+          n_edge->prev = p_edge;
+
+          if (p_edge->rev) {
+            p_edge->rev->rev = p_copy;
+          }
+          p_copy->rev = p_edge->rev;
+
+          p_edge->rev = n_copy;
+          n_copy->rev = p_edge;
+
+          *out++ = vert->edge;
+
+          if (vert->edge->face) {
+            if (vert->edge->face->edge == vert->edge) {
+              vert->edge->face->edge = n_edge;
+            }
+            vert->edge->face->n_edges--;
+            vert->edge->face = NULL;
+          }
+
+          vert->next->prev = vert->prev;
+          vert->prev->next = vert->next;
+
+          VertexInfo *n = vert->next;
+          delete vert;
+          return n;
+        }
+
+        template<typename out_iter_t>
+        size_t removeDegeneracies(VertexInfo *&begin, out_iter_t out) {
+          VertexInfo *v;
+          size_t count = 0;
+
+          while ((v = findDegenerateEar(begin)) != NULL) {
+            begin = clipEar(v, out);
+            ++count;
+          }
+          return count;
+        }
+
+        template<typename out_iter_t>
+        bool splitAndResume(VertexInfo *begin, out_iter_t out) {
+          diag_t diag;
+
+          diag = findDiagonal(begin);
+          if (diag == diag_t(NULL, NULL)) {
+            std::cerr << "failed to find diagonal" << std::endl;
+            return false;
+          }
+
+          // add a splitting edge between v1 and v2.
+          VertexInfo *v1 = diag.first;
+          VertexInfo *v2 = diag.second;
+
+          splitEdgeLoop(v1, v2);
+
+          v1->recompute();
+          v1->next->recompute();
+
+          v2->recompute();
+          v2->next->recompute();
+
+#if defined(CARVE_DEBUG)
+          dumpPoly(v1->edge, v2->edge);
+#endif
+
+#if defined(CARVE_DEBUG)
+          CARVE_ASSERT(!checkSelfIntersection(v1));
+          CARVE_ASSERT(!checkSelfIntersection(v2));
+#endif
+
+          bool r1 = doTriangulate(v1, out);
+          bool r2 =  doTriangulate(v2, out);
+
+          return r1 && r2;
+        }
+        
+        template<typename out_iter_t>
+        bool doTriangulate(VertexInfo *begin, out_iter_t out);
+
+        TriangulationData(proj_t _proj) : proj(_proj) {
+        }
+
+        VertexInfo *init(edge_t *begin) {
+          edge_t *e = begin;
+          VertexInfo *head = NULL, *tail = NULL, *v;
+          do {
+            VertexInfo *v = new VertexInfo(e, proj(e->vert->v));
+            if (tail != NULL) {
+              tail->next = v;
+              v->prev = tail;
+            } else {
+              head = v;
+            }
+            tail = v;
+
+            e = e->next;
+          } while (e != begin);
+          tail->next = head;
+          head->prev = tail;
+
+          v = head;
+          do {
+            v->recompute();
+            v = v->next;
+          } while (v != head);
+          return head;
+        }
+
+        class EarQueue {
+          TriangulationData &data;
+          std::vector<VertexInfo *> queue;
+
+          void checkheap() {
+#ifdef __GNUC__
+            CARVE_ASSERT(std::__is_heap(queue.begin(), queue.end(), order_by_score()));
+#endif
+          }
+
+        public:
+          EarQueue(TriangulationData &_data) : data(_data), queue() {
+          }
+
+          size_t size() const {
+            return queue.size();
+          }
+
+          void push(VertexInfo *v) {
+#if defined(CARVE_DEBUG)
+            checkheap();
+#endif
+            queue.push_back(v);
+            std::push_heap(queue.begin(), queue.end(), order_by_score());
+          }
+
+          VertexInfo *pop() {
+#if defined(CARVE_DEBUG)
+            checkheap();
+#endif
+            std::pop_heap(queue.begin(), queue.end(), order_by_score());
+            VertexInfo *v = queue.back();
+            queue.pop_back();
+            return v;
+          }
+
+          void remove(VertexInfo *v) {
+#if defined(CARVE_DEBUG)
+            checkheap();
+#endif
+            CARVE_ASSERT(std::find(queue.begin(), queue.end(), v) != queue.end());
+            double score = v->score;
+            if (v != queue[0]) {
+              v->score = queue[0]->score + 1;
+              std::make_heap(queue.begin(), queue.end(), order_by_score());
+            }
+            CARVE_ASSERT(v == queue[0]);
+            std::pop_heap(queue.begin(), queue.end(), order_by_score());
+            CARVE_ASSERT(queue.back() == v);
+            queue.pop_back();
+            v->score = score;
+          }
+
+          void changeScore(VertexInfo *v, double s_from, double s_to) {
+#if defined(CARVE_DEBUG)
+            checkheap();
+#endif
+            CARVE_ASSERT(std::find(queue.begin(), queue.end(), v) != queue.end());
+            if (s_from != s_to) {
+              v->score = s_to;
+              std::make_heap(queue.begin(), queue.end(), order_by_score());
+            }
+          }
+
+          void update(VertexInfo *v) {
+            VertexInfo pre = *v;
+            v->recompute();
+            VertexInfo post = *v;
+
+            if (pre.isCandidate()) {
+              if (post.isCandidate()) {
+                changeScore(v, pre.score, post.score);
+              } else {
+                remove(v);
+              }
+            } else {
+              if (post.isCandidate()) {
+                push(v);
+              }
+            }
+          }
+        };
+
+
+        bool checkSelfIntersection(const VertexInfo *vert) {
+          const VertexInfo *v1 = vert;
+          do {
+            const VertexInfo *v2 = vert->next->next;
+            do {
+              carve::geom2d::P2 a = v1->p;
+              carve::geom2d::P2 b = v1->next->p;
+              CARVE_ASSERT(a == proj(v1->edge->vert->v));
+              CARVE_ASSERT(b == proj(v1->edge->next->vert->v));
+
+              carve::geom2d::P2 c = v2->p;
+              carve::geom2d::P2 d = v2->next->p;
+              CARVE_ASSERT(c == proj(v2->edge->vert->v));
+              CARVE_ASSERT(d == proj(v2->edge->next->vert->v));
+
+              bool intersected = false;
+              if (a == c || a == d || b == c || b == d) {
+              } else {
+                intersected = true;
+
+                double l_a1 = carve::geom2d::orient2d(a, b, c);
+                double l_a2 = carve::geom2d::orient2d(a, b, d);
+                if (l_a1 > l_a2) std::swap(l_a1, l_a2);
+                if (l_a2 <= 0.0 || l_a1 >= 0.0) {
+                  intersected = false;
+                }
+
+                double l_b1 = carve::geom2d::orient2d(c, d, a);
+                double l_b2 = carve::geom2d::orient2d(c, d, b);
+                if (l_b1 > l_b2) std::swap(l_b1, l_b2);
+                if (l_b2 <= 0.0 || l_b1 >= 0.0) {
+                  intersected = false;
+                }
+
+                if (l_a1 == 0.0 && l_a2 == 0.0 && l_b1 == 0.0 && l_b2 == 0.0) {
+                  if (std::max(a.x, b.x) >= std::min(c.x, d.x) && std::min(a.x, b.x) <= std::max(c.x, d.x)) {
+                    // colinear and intersecting.
+                  } else {
+                    // colinear but not intersecting.
+                    intersected = false;
+                  }
+                }
+              }
+              if (intersected) {
+                carve::geom2d::P2 p[4] = { a, b, c, d };
+                carve::geom::aabb<2> A(p, p+4);
+                A.expand(5);
+
+                std::cerr << "\
+<?xml version=\"1.0\" encoding=\"utf-8\"?>\n\
+<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n\
+<svg version=\"1.1\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"\n\
+  x=\"" << A.min().x << "px\" y=\"" << A.min().y << "\"\n\
+  width=\"" << A.extent.x * 2 << "\" height=\"" << A.extent.y * 2 << "\"\n\
+  viewBox=\"" << A.min().x << " " << A.min().y << " " << A.max().x << " " << A.max().y << "\"\n\
+  enable-background=\"new " << A.min().x << " " << A.min().y << " " << A.max().x << " " << A.max().y << "\"\n\
+  xml:space=\"preserve\">\n\
+<line fill=\"none\" stroke=\"#000000\" x1=\"" << a.x << "\" y1=\"" << a.y << "\" x2=\"" << b.x << "\" y2=\"" << b.y << "\"/>\n\
+<line fill=\"none\" stroke=\"#000000\" x1=\"" << c.x << "\" y1=\"" << c.y << "\" x2=\"" << d.x << "\" y2=\"" << d.y << "\"/>\n\
+</svg>\n";
+                return true;
+              }
+              v2 = v2->next;
+            } while (v2 != vert);
+            v1 = v1->next;
+          } while (v1 != vert);
+          return false;
+        }
+
+        carve::geom::aabb<2> make2d(const edge_t *edge, std::vector<geom2d::P2> &points) {
+          const edge_t *e = edge;
+          do {
+            points.push_back(P(e));
+            e = e->next;
+          } while(e != edge);
+          return carve::geom::aabb<2>(points.begin(), points.end());
+        }
+
+        void dumpLoop(std::ostream &out,
+                      const std::vector<carve::geom2d::P2> &points,
+                      const char *fill,
+                      const char *stroke,
+                      double stroke_width,
+                      double offx,
+                      double offy,
+                      double scale
+                      ) {
+          out << "<polygon fill=\"" << fill << "\" stroke=\"" << stroke << "\" stroke-width=\"" << stroke_width << "\" points=\"";
+          for (size_t i = 0; i < points.size(); ++i) {
+            if (i) out << ' ';
+            double x, y;
+            x = scale * (points[i].x - offx) + 5;
+            y = scale * (points[i].y - offy) + 5;
+            out << x << ',' << y;
+          }
+          out << "\" />" << std::endl;
+        }
+
+        void dumpPoly(const edge_t *edge, const edge_t *edge2 = NULL, const char *pfx = "poly_") {
+          static int step = 0;
+          std::ostringstream filename;
+          filename << pfx << step++ << ".svg";
+          std::cerr << "dumping to " << filename.str() << std::endl;
+          std::ofstream out(filename.str().c_str());
+
+          std::vector <geom2d::P2> points, points2;
+
+          carve::geom::aabb<2> A = make2d(edge, points);
+          if (edge2) {
+            A.unionAABB(make2d(edge2, points2));
+          }
+          A.expand(5);
+
+          out << "\
+<?xml version=\"1.0\"?>\n\
+<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">\n\
+<svg\n\
+  x=\"" << A.min().x << "px\" y=\"" << A.min().y << "\"\n\
+  width=\"" << A.extent.x * 2 << "\" height=\"" << A.extent.y * 2 << "\"\n\
+  viewBox=\"" << A.min().x << " " << A.min().y << " " << A.max().x << " " << A.max().y << "\"\n\
+  enable-background=\"new " << A.min().x << " " << A.min().y << " " << A.max().x << " " << A.max().y << "\"\n\
+  xml:space=\"preserve\">\n";
+
+          dumpLoop(out, points, "rgb(0,0,0)", "blue", 0.1, 0, 0, 1);
+          if (points2.size()) dumpLoop(out, points2, "rgb(255,0,0)", "blue", 0.1, 0, 0, 1);
+
+          out << "</svg>" << std::endl;
+        }
+      };
+
+      template<unsigned ndim, typename proj_t>
+      template<typename out_iter_t>
+      bool TriangulationData<ndim, proj_t>::doTriangulate(VertexInfo *begin, out_iter_t out) {
+        EarQueue vq(*this);
+
+#if defined(CARVE_DEBUG)
+        dumpPoly(begin->edge, NULL, "input_");
+        CARVE_ASSERT(!checkSelfIntersection(begin));
+#endif
+
+        VertexInfo *v = begin, *n, *p;
+        size_t remain = 0;
+        do {
+          if (v->isCandidate()) vq.push(v);
+          v = v->next;
+          remain++;
+        } while (v != begin);
+
+        while (remain > 3 && vq.size()) {
+          { static int __c = 0; if (++__c % 50 == 0) { break; } }
+          v = vq.pop();
+          if (!v->isClipable()) {
+            v->fail();
+            continue;
+          }
+
+        continue_clipping:
+          n = clipEar(v, out);
+          p = n->prev;
+          begin = n;
+          if (--remain == 3) break;
+          // if (checkSelfIntersection(begin)) {
+          //   dumpPoly(begin->edge, NULL, "badclip_");
+          //   CARVE_ASSERT(!!!"clip created self intersection");
+          // }
+
+          vq.update(n);
+          vq.update(p);
+
+          if (n->score < p->score) { std::swap(n, p); }
+          if (n->score > 0.25 && n->isCandidate() && n->isClipable()) {
+            vq.remove(n);
+            v = n;
+            goto continue_clipping;
+          }
+          if (p->score > 0.25 && p->isCandidate() && p->isClipable()) {
+            vq.remove(p);
+            v = p;
+            goto continue_clipping;
+          }
+        }
+
+        bool ret = false;
+
+#if defined(CARVE_DEBUG)
+        dumpPoly(begin->edge, NULL, "remainder_");
+#endif
+
+        if (remain > 3) {
+          std::vector<carve::geom2d::P2> temp;
+          temp.reserve(remain);
+          VertexInfo *v = begin;
+          do {
+            temp.push_back(P(v));
+            v = v->next;
+          } while (v != begin);
+
+          if (carve::geom2d::signedArea(temp) == 0) {
+            // XXX: this test will fail in cases where the boundary is
+            // twisted so that a negative area balances a positive area.
+            std::cerr << "got to here" << std::endl;
+            dumpPoly(begin->edge, NULL, "interesting_case_");
+            goto done;
+          }
+        }
+
+        if (remain > 3) {
+          remain -= removeDegeneracies(begin, out);
+        }
+
+        if (remain > 3) {
+          return splitAndResume(begin, out);
+        }
+
+        { double a = loopArea(begin->edge, proj); CARVE_ASSERT(a <= 0.0); }
+        *out++ = begin->edge;
+
+        v = begin;
+        do {
+          n = v->next;
+          delete v;
+          v = n;
+        } while (v != begin);
+
+        ret = true;
+
+      done:
+        return ret;
+      }
+    }
+
+
+
+    template<unsigned ndim, typename proj_t, typename out_iter_t>
+    void triangulate(Edge<ndim> *edge, proj_t proj, out_iter_t out) {
+      detail::TriangulationData<ndim, proj_t> triangulator(proj);
+      typename detail::TriangulationData<ndim, proj_t>::VertexInfo *v = triangulator.init(edge);
+      triangulator.removeDegeneracies(v, out);
+      triangulator.doTriangulate(v, out);
+    }
+
+    // given edge a-b, part of triangles a-b-c and b-a-d, make triangles c-a-d and b-c-d
+    template<unsigned ndim>
+    void flipTriEdge(Edge<ndim> *edge) {
+      CARVE_ASSERT(edge->rev != NULL);
+      CARVE_ASSERT(edge->face->nEdges() == 3);
+      CARVE_ASSERT(edge->rev->face->nEdges() == 3);
+
+      CARVE_ASSERT(edge->prev != edge);
+      CARVE_ASSERT(edge->next != edge);
+      CARVE_ASSERT(edge->rev->prev != edge->rev);
+      CARVE_ASSERT(edge->rev->next != edge->rev);
+
+      typedef Edge<ndim> edge_t;
+      typedef Face<ndim> face_t;
+
+      edge_t *t1[3], *t2[3];
+      face_t *f1, *f2;
+
+      t1[1] = edge; t2[1] = edge->rev;
+      t1[0] = t1[1]->prev; t1[2] = t1[1]->next;
+      t2[0] = t2[1]->prev; t2[2] = t2[1]->next;
+
+      f1 = t1[1]->face; f2 = t2[1]->face;
+
+      // std::cerr << t1[0]->vert << "->" << t1[1]->vert << "->" << t1[2]->vert << std::endl;
+      // std::cerr << t2[0]->vert << "->" << t2[1]->vert << "->" << t2[2]->vert << std::endl;
+
+      t1[1]->vert = t2[0]->vert;
+      t2[1]->vert = t1[0]->vert;
+
+      // std::cerr << t1[0]->vert << "->" << t2[2]->vert << "->" << t1[1]->vert << std::endl;
+      // std::cerr << t2[0]->vert << "->" << t1[2]->vert << "->" << t2[1]->vert << std::endl;
+
+      detail::link(t1[0], t2[2], t1[1], f1);
+      detail::link(t2[0], t1[2], t2[1], f2);
+
+      if (t1[0]->rev) CARVE_ASSERT(t1[0]->v2() == t1[0]->rev->v1());
+      if (t2[0]->rev) CARVE_ASSERT(t2[0]->v2() == t2[0]->rev->v1());
+      if (t1[2]->rev) CARVE_ASSERT(t1[2]->v2() == t1[2]->rev->v1());
+      if (t2[2]->rev) CARVE_ASSERT(t2[2]->v2() == t2[2]->rev->v1());
+    }
+
+    template<unsigned ndim>
+    void splitEdgeLoop(Edge<ndim> *v1, Edge<ndim> *v2) {
+      // v1 and v2 end up on different sides of the split.
+      Edge<ndim> *v1_copy = new Edge<ndim>(v1->vert, NULL);
+      Edge<ndim> *v2_copy = new Edge<ndim>(v2->vert, NULL);
+
+      v1_copy->rev = v2_copy;
+      v2_copy->rev = v1_copy;
+
+      v1_copy->prev = v1->prev;
+      v1_copy->next = v2;
+
+      v2_copy->prev = v2->prev;
+      v2_copy->next = v1;
+
+      v1->prev->next = v1_copy;
+      v1->prev = v2_copy;
+
+      v2->prev->next = v2_copy;
+      v2->prev = v1_copy;
+    }
+
+    template<unsigned ndim>
+    Edge<ndim> *clipVertex(Edge<ndim> *edge) {
+      Edge<ndim> *prev = edge->prev;
+      Edge<ndim> *next = edge->next;
+      splitEdgeLoop(edge->prev, edge->next);
+      return next;
+    }
+  }
+}
diff --git a/extern/carve/include/carve/mesh_simplify.hpp b/extern/carve/include/carve/mesh_simplify.hpp
new file mode 100644
index 00000000000..1c5169caf58
--- /dev/null
+++ b/extern/carve/include/carve/mesh_simplify.hpp
@@ -0,0 +1,1574 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+#include <carve/mesh.hpp>
+#include <carve/mesh_ops.hpp>
+#include <carve/geom2d.hpp>
+#include <carve/heap.hpp>
+#include <carve/rtree.hpp>
+#include <carve/triangle_intersection.hpp>
+
+#include <fstream>
+#include <string>
+#include <utility>
+#include <set>
+#include <algorithm>
+#include <vector>
+
+#include "write_ply.hpp"
+
+
+namespace carve {
+  namespace mesh {
+
+
+    class MeshSimplifier {
+      typedef carve::mesh::MeshSet<3> meshset_t;
+      typedef carve::mesh::Mesh<3> mesh_t;
+      typedef mesh_t::vertex_t vertex_t;
+      typedef vertex_t::vector_t vector_t;
+      typedef mesh_t::edge_t edge_t;
+      typedef mesh_t::face_t face_t;
+      typedef face_t::aabb_t aabb_t;
+
+      typedef carve::geom::RTreeNode<3, carve::mesh::Face<3> *> face_rtree_t;
+
+
+      struct EdgeInfo {
+        edge_t *edge;
+        double delta_v;
+
+        double c[4];
+        double l[2], t1[2], t2[2];
+        size_t heap_idx;
+
+        void update() {
+          const vertex_t *v1 = edge->vert;
+          const vertex_t *v2 = edge->next->vert;
+          const vertex_t *v3 = edge->next->next->vert;
+          const vertex_t *v4 = edge->rev ? edge->rev->next->next->vert : NULL;
+
+          l[0] = (v1->v - v2->v).length();
+
+          t1[0] = (v3->v - v1->v).length();
+          t1[1] = (v3->v - v2->v).length();
+
+          c[0] = std::max((t1[0] + t1[1]) / l[0] - 1.0, 0.0);
+
+          if (v4) {
+            l[1] = (v3->v - v4->v).length();
+            t2[0] = (v4->v - v1->v).length();
+            t2[1] = (v4->v - v2->v).length();
+            c[1] = std::max((t2[0] + t2[1]) / l[0] - 1.0, 0.0);
+            c[2] = std::max((t1[0] + t2[0]) / l[1] - 1.0, 0.0);
+            c[3] = std::max((t1[1] + t2[1]) / l[1] - 1.0, 0.0);
+            delta_v = carve::geom3d::tetrahedronVolume(v1->v, v2->v, v3->v, v4->v);
+          } else {
+            l[1] = 0.0;
+            t2[0] = t2[1] = 0.0;
+            c[1] = c[2] = c[3] = 0.0;
+            delta_v = 0.0;
+          }
+        }
+
+        EdgeInfo(edge_t *e) : edge(e) {
+          update();
+        }
+
+        EdgeInfo() : edge(NULL) {
+          delta_v = 0.0;
+          c[0] = c[1] = c[2] = c[3] = 0.0;
+          l[0] = l[1] = 0.0;
+          t1[0] = t1[1] = 0.0;
+          t2[0] = t2[1] = 0.0;
+        }
+
+        struct NotifyPos {
+          void operator()(EdgeInfo *edge, size_t pos) const { edge->heap_idx = pos; }
+          void operator()(EdgeInfo &edge, size_t pos) const { edge.heap_idx = pos; }
+        };
+      };
+
+
+
+      struct FlippableBase {
+        double min_dp;
+
+        FlippableBase(double _min_dp = 0.0) : min_dp(_min_dp) {
+        }
+
+        bool open(const EdgeInfo *e) const {
+          return e->edge->rev == NULL;
+        }
+
+        bool wouldCreateDegenerateEdge(const EdgeInfo *e) const {
+          return e->edge->prev->vert == e->edge->rev->prev->vert;
+        }
+
+        bool flippable_DotProd(const EdgeInfo *e) const { 
+          using carve::geom::dot;
+          using carve::geom::cross;
+
+          if (open(e)) return false;
+
+          edge_t *edge = e->edge;
+
+          const vertex_t *v1 = edge->vert;
+          const vertex_t *v2 = edge->next->vert;
+          const vertex_t *v3 = edge->next->next->vert;
+          const vertex_t *v4 = edge->rev->next->next->vert;
+
+          if (dot(cross(v3->v - v2->v, v1->v - v2->v).normalized(),
+                  cross(v4->v - v1->v, v2->v - v1->v).normalized()) < min_dp) return false;
+
+          if (dot(cross(v3->v - v4->v, v1->v - v4->v).normalized(),
+                  cross(v4->v - v3->v, v2->v - v3->v).normalized()) < min_dp) return false;
+
+          return true;
+        }
+
+        virtual bool canFlip(const EdgeInfo *e) const {
+          return !open(e) && !wouldCreateDegenerateEdge(e) && score(e) > 0.0;
+        }
+
+        virtual double score(const EdgeInfo *e) const {
+          return std::min(e->c[2], e->c[3]) - std::min(e->c[0], e->c[1]);
+        }
+
+        class Priority {
+          Priority &operator=(const Priority &);
+          const FlippableBase &flip;
+
+        public:
+          Priority(const FlippableBase &_flip) : flip(_flip) {}
+          bool operator()(const EdgeInfo *a, const EdgeInfo *b) const { return flip.score(a) > flip.score(b); }
+        };
+
+        Priority priority() const {
+          return Priority(*this);
+        }
+      };
+
+
+
+      struct FlippableConservative : public FlippableBase {
+        FlippableConservative() : FlippableBase(0.0) {
+        }
+
+        bool connectsAlmostCoplanarFaces(const EdgeInfo *e) const {
+          // XXX: remove hard coded constants.
+          if (e->c[0] < 1e-10 || e->c[1] < 1e-10) return true;
+          return fabs(carve::geom::dot(e->edge->face->plane.N, e->edge->rev->face->plane.N) - 1.0) < 1e-10;
+        }
+
+        bool connectsExactlyCoplanarFaces(const EdgeInfo *e) const {
+          edge_t *edge = e->edge;
+          return
+            carve::geom3d::orient3d(edge->vert->v,
+                                    edge->next->vert->v,
+                                    edge->next->next->vert->v,
+                                    edge->rev->next->next->vert->v) == 0.0 &&
+            carve::geom3d::orient3d(edge->rev->vert->v,
+                                    edge->rev->next->vert->v,
+                                    edge->rev->next->next->vert->v,
+                                    edge->next->next->vert->v) == 0.0;
+        }
+
+        virtual bool canFlip(const EdgeInfo *e) const {
+          return FlippableBase::canFlip(e) && connectsExactlyCoplanarFaces(e) && flippable_DotProd(e);
+        }
+      };
+
+
+
+      struct FlippableColinearPair : public FlippableBase {
+
+        FlippableColinearPair() {
+        }
+
+
+        virtual double score(const EdgeInfo *e) const {
+          return e->l[0] - e->l[1];
+        }
+
+        virtual bool canFlip(const EdgeInfo *e) const {
+          if (!FlippableBase::canFlip(e)) return false;
+
+          if (e->c[0] > 1e-3 || e->c[1] > 1e-3) return false;
+
+          return true;
+        }
+      };
+
+
+
+      struct Flippable : public FlippableBase {
+        double min_colinearity;
+        double min_delta_v;
+
+        Flippable(double _min_colinearity,
+                  double _min_delta_v,
+                  double _min_normal_angle) :
+            FlippableBase(cos(_min_normal_angle)),
+            min_colinearity(_min_colinearity),
+            min_delta_v(_min_delta_v) {
+        }
+
+
+        virtual bool canFlip(const EdgeInfo *e) const {
+          if (!FlippableBase::canFlip(e)) return false;
+
+          if (fabs(e->delta_v) > min_delta_v) return false;
+
+          // if (std::min(e->c[0], e->c[1]) > min_colinearity) return false;
+
+          return flippable_DotProd(e);
+        }
+      };
+
+
+
+      struct EdgeMerger {
+        double min_edgelen;
+
+        virtual bool canMerge(const EdgeInfo *e) const {
+          return e->l[0] <= min_edgelen;
+        }
+
+        EdgeMerger(double _min_edgelen) : min_edgelen(_min_edgelen) {
+        }
+
+        double score(const EdgeInfo *e) const {
+          return min_edgelen - e->l[0];
+        }
+
+        class Priority {
+          Priority &operator=(const Priority &);
+
+        public:
+          const EdgeMerger &merger;
+          Priority(const EdgeMerger &_merger) : merger(_merger) {
+          }
+          bool operator()(const EdgeInfo *a, const EdgeInfo *b) const {
+            // collapse edges in order from shortest to longest.
+            return merger.score(a) < merger.score(b);
+          }
+        };
+
+        Priority priority() const {
+          return Priority(*this);
+        }
+      };
+
+
+
+      typedef std::unordered_map<edge_t *, EdgeInfo *> edge_info_map_t;
+      std::unordered_map<edge_t *, EdgeInfo *> edge_info;
+
+
+
+      void initEdgeInfo(mesh_t *mesh) {
+        for (size_t i = 0; i < mesh->faces.size(); ++i) {
+          edge_t *e = mesh->faces[i]->edge;
+          do {
+            edge_info[e] = new EdgeInfo(e);
+            e = e->next;
+          } while (e != mesh->faces[i]->edge);
+        }
+      }
+
+
+
+      void initEdgeInfo(meshset_t *meshset) {
+        for (size_t m = 0; m < meshset->meshes.size(); ++m) {
+          mesh_t *mesh = meshset->meshes[m];
+          initEdgeInfo(mesh);
+        }
+      }
+
+
+
+      void clearEdgeInfo() {
+        for (edge_info_map_t::iterator i = edge_info.begin(); i != edge_info.end(); ++i) {
+          delete (*i).second;
+        }
+      }
+
+
+
+      void updateEdgeFlipHeap(std::vector<EdgeInfo *> &edge_heap,
+                              edge_t *edge,
+                              const FlippableBase &flipper) {
+        std::unordered_map<edge_t *, EdgeInfo *>::const_iterator i = edge_info.find(edge);
+        CARVE_ASSERT(i != edge_info.end());
+        EdgeInfo *e = (*i).second;
+
+        bool heap_pre = e->heap_idx != ~0U;
+        (*i).second->update();
+        bool heap_post = edge->v1() < edge->v2() && flipper.canFlip(e);
+
+        if (!heap_pre && heap_post) {
+          edge_heap.push_back(e);
+          carve::heap::push_heap(edge_heap.begin(),
+                                 edge_heap.end(),
+                                 flipper.priority(),
+                                 EdgeInfo::NotifyPos());
+        } else if (heap_pre && !heap_post) {
+          CARVE_ASSERT(edge_heap[e->heap_idx] == e);
+          carve::heap::remove_heap(edge_heap.begin(),
+                                   edge_heap.end(),
+                                   edge_heap.begin() + e->heap_idx,
+                                   flipper.priority(),
+                                   EdgeInfo::NotifyPos());
+          CARVE_ASSERT(edge_heap.back() == e);
+          edge_heap.pop_back();
+          e->heap_idx = ~0U;
+        } else if (heap_pre && heap_post) {
+          CARVE_ASSERT(edge_heap[e->heap_idx] == e);
+          carve::heap::adjust_heap(edge_heap.begin(),
+                                   edge_heap.end(),
+                                   edge_heap.begin() + e->heap_idx,
+                                   flipper.priority(),
+                                   EdgeInfo::NotifyPos());
+          CARVE_ASSERT(edge_heap[e->heap_idx] == e);
+        }
+      }
+
+
+      std::string vk(const vertex_t *v1,
+                     const vertex_t *v2,
+                     const vertex_t *v3) {
+        const vertex_t *v[3];
+        v[0] = v1; v[1] = v2; v[2] = v3;
+        std::sort(v, v+3);
+        std::ostringstream s;
+        s << v[0] << ";" << v[1] << ";" << v[2];
+        return s.str();
+      }
+
+      std::string vk(const face_t *f) { return vk(f->edge->vert, f->edge->next->vert, f->edge->next->next->vert); }
+
+      int mapTriangle(const face_t *face,
+                      const vertex_t *remap1, const vertex_t *remap2,
+                      const vector_t &tgt,
+                      vector_t tri[3]) {
+        edge_t *edge = face->edge;
+        int n_remaps = 0;
+        for (size_t i = 0; i < 3; edge = edge->next, ++i) {
+          if      (edge->vert == remap1) { tri[i] = tgt; ++n_remaps; }
+          else if (edge->vert == remap2) { tri[i] = tgt; ++n_remaps; }
+          else                           { tri[i] = edge->vert->v;   }
+        }
+        return n_remaps;
+      }
+
+      template<typename iter1_t, typename iter2_t>
+      int countIntersectionPairs(iter1_t fabegin, iter1_t faend,
+                                 iter2_t fbbegin, iter2_t fbend,
+                                 const vertex_t *remap1, const vertex_t *remap2,
+                                 const vector_t &tgt) {
+        vector_t tri_a[3], tri_b[3];
+        int remap_a, remap_b;
+        std::set<std::pair<const face_t *, const face_t *> > ints;
+
+        for (iter1_t i = fabegin; i != faend; ++i) {
+          remap_a = mapTriangle(*i, remap1, remap2, tgt, tri_a);
+          if (remap_a >= 2) continue;
+          for (iter2_t j = fbbegin; j != fbend; ++j) {
+            remap_b = mapTriangle(*j, remap1, remap2, tgt, tri_b);
+            if (remap_b >= 2) continue;
+            if (carve::geom::triangle_intersection_exact(tri_a, tri_b) == carve::geom::TR_TYPE_INT) {
+              ints.insert(std::make_pair(std::min(*i, *j), std::max(*i, *j)));
+            }
+          }
+        }
+
+        return ints.size();
+      }
+
+      int countIntersections(const vertex_t *v1,
+                             const vertex_t *v2,
+                             const vertex_t *v3,
+                             const std::vector<face_t *> &faces) {
+        int n_int = 0;
+        vector_t tri_a[3], tri_b[3];
+        tri_a[0] = v1->v;
+        tri_a[1] = v2->v;
+        tri_a[2] = v3->v;
+
+        for (std::vector<face_t *>::const_iterator i = faces.begin(); i != faces.end(); ++i) {
+          face_t *fb = *i;
+          if (fb->nEdges() != 3) continue;
+          tri_b[0] = fb->edge->vert->v;
+          tri_b[1] = fb->edge->next->vert->v;
+          tri_b[2] = fb->edge->next->next->vert->v;
+
+          if (carve::geom::triangle_intersection_exact(tri_a, tri_b) == carve::geom::TR_TYPE_INT) {
+            n_int++;
+          }
+        }
+        return n_int;
+      }
+
+
+
+      int _findSelfIntersections(const face_rtree_t *a_node,
+                                 const face_rtree_t *b_node,
+                                 bool descend_a = true) {
+        int r = 0;
+
+        if (!a_node->bbox.intersects(b_node->bbox)) {
+          return 0;
+        }
+
+        if (a_node->child && (descend_a || !b_node->child)) {
+          for (face_rtree_t *node = a_node->child; node; node = node->sibling) {
+            r += _findSelfIntersections(node, b_node, false);
+          }
+        } else if (b_node->child) {
+          for (face_rtree_t *node = b_node->child; node; node = node->sibling) {
+            r += _findSelfIntersections(a_node, node, true);
+          }
+        } else {
+          for (size_t i = 0; i < a_node->data.size(); ++i) {
+            face_t *fa = a_node->data[i];
+            if (fa->nVertices() != 3) continue;
+
+            aabb_t aabb_a = fa->getAABB();
+
+            vector_t tri_a[3];
+            tri_a[0] = fa->edge->vert->v;
+            tri_a[1] = fa->edge->next->vert->v;
+            tri_a[2] = fa->edge->next->next->vert->v;
+
+            if (!aabb_a.intersects(b_node->bbox)) continue;
+
+            for (size_t j = 0; j < b_node->data.size(); ++j) {
+              face_t *fb = b_node->data[j];
+              if (fb->nVertices() != 3) continue;
+
+              vector_t tri_b[3];
+              tri_b[0] = fb->edge->vert->v;
+              tri_b[1] = fb->edge->next->vert->v;
+              tri_b[2] = fb->edge->next->next->vert->v;
+              
+              if (carve::geom::triangle_intersection_exact(tri_a, tri_b) == carve::geom::TR_TYPE_INT) {
+                ++r;
+              }
+            }
+          }
+        }
+
+        return r;
+      }
+
+
+
+      int countSelfIntersections(meshset_t *meshset) {
+        int n_ints = 0;
+        face_rtree_t *tree = face_rtree_t::construct_STR(meshset->faceBegin(), meshset->faceEnd(), 4, 4);
+
+        for (meshset_t::face_iter f = meshset->faceBegin(); f != meshset->faceEnd(); ++f) {
+          face_t *fa = *f;
+          if (fa->nVertices() != 3) continue;
+
+          vector_t tri_a[3];
+          tri_a[0] = fa->edge->vert->v;
+          tri_a[1] = fa->edge->next->vert->v;
+          tri_a[2] = fa->edge->next->next->vert->v;
+
+          std::vector<face_t *> near_faces;
+          tree->search(fa->getAABB(), std::back_inserter(near_faces));
+
+          for (size_t f2 = 0; f2 < near_faces.size(); ++f2) {
+            const face_t *fb = near_faces[f2];
+            if (fb->nVertices() != 3) continue;
+
+            if (fa >= fb) continue;
+
+            vector_t tri_b[3];
+            tri_b[0] = fb->edge->vert->v;
+            tri_b[1] = fb->edge->next->vert->v;
+            tri_b[2] = fb->edge->next->next->vert->v;
+
+            if (carve::geom::triangle_intersection_exact(tri_a, tri_b) == carve::geom::TR_TYPE_INT) {
+              ++n_ints;
+            }
+          }
+        }
+
+        delete tree;
+
+        return n_ints;
+      }
+
+      size_t flipEdges(meshset_t *mesh,
+                       const FlippableBase &flipper) {
+        face_rtree_t *tree = face_rtree_t::construct_STR(mesh->faceBegin(), mesh->faceEnd(), 4, 4);
+
+        size_t n_mods = 0;
+
+        std::vector<EdgeInfo *> edge_heap;
+
+        edge_heap.reserve(edge_info.size());
+
+        for (edge_info_map_t::iterator i = edge_info.begin();
+             i != edge_info.end();
+             ++i) {
+          EdgeInfo *e = (*i).second;
+          e->update();
+          if (e->edge->v1() < e->edge->v2() && flipper.canFlip(e)) {
+            edge_heap.push_back(e);
+          } else {
+            e->heap_idx = ~0U;
+          }
+        }
+
+        carve::heap::make_heap(edge_heap.begin(),
+                               edge_heap.end(),
+                               flipper.priority(),
+                               EdgeInfo::NotifyPos());
+
+        while (edge_heap.size()) {
+//           std::cerr << "test" << std::endl;
+//           for (size_t m = 0; m < mesh->meshes.size(); ++m) {
+//             for (size_t f = 0; f < mesh->meshes[m]->faces.size(); ++f) {
+//               if (mesh->meshes[m]->faces[f]->edge) mesh->meshes[m]->faces[f]->edge->validateLoop();
+//             }
+//           }
+
+          carve::heap::pop_heap(edge_heap.begin(),
+                                edge_heap.end(),
+                                flipper.priority(),
+                                EdgeInfo::NotifyPos());
+          EdgeInfo *e = edge_heap.back();
+//           std::cerr << "flip " << e << std::endl;
+          edge_heap.pop_back();
+          e->heap_idx = ~0U;
+
+          aabb_t aabb;
+          aabb = e->edge->face->getAABB();
+          aabb.unionAABB(e->edge->rev->face->getAABB());
+
+          std::vector<face_t *> overlapping;
+          tree->search(aabb, std::back_inserter(overlapping));
+
+          // overlapping.erase(e->edge->face);
+          // overlapping.erase(e->edge->rev->face);
+
+          const vertex_t *v1 = e->edge->vert;
+          const vertex_t *v2 = e->edge->next->vert;
+          const vertex_t *v3 = e->edge->next->next->vert;
+          const vertex_t *v4 = e->edge->rev->next->next->vert;
+
+          int n_int1 = countIntersections(v1, v2, v3, overlapping);
+          int n_int2 = countIntersections(v2, v1, v4, overlapping);
+          int n_int3 = countIntersections(v3, v4, v2, overlapping);
+          int n_int4 = countIntersections(v4, v3, v1, overlapping);
+
+          if ((n_int3 + n_int4) - (n_int1 + n_int2) > 0) {
+            std::cerr << "delta[ints] = " << (n_int3 + n_int4) - (n_int1 + n_int2) << std::endl;
+            // avoid creating a self intersection.
+            continue;
+          }
+
+          n_mods++;
+          CARVE_ASSERT(flipper.canFlip(e));
+          edge_info[e->edge]->update();
+          edge_info[e->edge->rev]->update();
+
+          carve::mesh::flipTriEdge(e->edge);
+
+          tree->updateExtents(aabb);
+
+          updateEdgeFlipHeap(edge_heap, e->edge, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->rev, flipper);
+
+          CARVE_ASSERT(!flipper.canFlip(e));
+
+          updateEdgeFlipHeap(edge_heap, e->edge->next, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->next->next, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->rev->next, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->rev->next->next, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->next->rev, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->next->next->rev, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->rev->next->rev, flipper);
+          updateEdgeFlipHeap(edge_heap, e->edge->rev->next->next->rev, flipper);
+        }
+
+        delete tree;
+
+        return n_mods;
+      }
+
+
+
+      void removeFromEdgeMergeHeap(std::vector<EdgeInfo *> &edge_heap,
+                                   EdgeInfo *edge,
+                                   const EdgeMerger &merger) {
+        if (edge->heap_idx != ~0U) {
+          CARVE_ASSERT(edge_heap[edge->heap_idx] == edge);
+          carve::heap::remove_heap(edge_heap.begin(),
+                                   edge_heap.end(),
+                                   edge_heap.begin() + edge->heap_idx,
+                                   merger.priority(),
+                                   EdgeInfo::NotifyPos());
+          CARVE_ASSERT(edge_heap.back() == edge);
+          edge_heap.pop_back();
+          edge->heap_idx = ~0U;
+        }
+      }
+
+      void updateEdgeMergeHeap(std::vector<EdgeInfo *> &edge_heap,
+                               EdgeInfo *edge,
+                               const EdgeMerger &merger) {
+        bool heap_pre = edge->heap_idx != ~0U;
+        edge->update();
+        bool heap_post = merger.canMerge(edge);
+
+        if (!heap_pre && heap_post) {
+          edge_heap.push_back(edge);
+          carve::heap::push_heap(edge_heap.begin(),
+                                 edge_heap.end(),
+                                 merger.priority(),
+                                 EdgeInfo::NotifyPos());
+        } else if (heap_pre && !heap_post) {
+          CARVE_ASSERT(edge_heap[edge->heap_idx] == edge);
+          carve::heap::remove_heap(edge_heap.begin(),
+                                   edge_heap.end(),
+                                   edge_heap.begin() + edge->heap_idx,
+                                   merger.priority(),
+                                   EdgeInfo::NotifyPos());
+          CARVE_ASSERT(edge_heap.back() == edge);
+          edge_heap.pop_back();
+          edge->heap_idx = ~0U;
+        } else if (heap_pre && heap_post) {
+          CARVE_ASSERT(edge_heap[edge->heap_idx] == edge);
+          carve::heap::adjust_heap(edge_heap.begin(),
+                                   edge_heap.end(),
+                                   edge_heap.begin() + edge->heap_idx,
+                                   merger.priority(),
+                                   EdgeInfo::NotifyPos());
+          CARVE_ASSERT(edge_heap[edge->heap_idx] == edge);
+        }
+      }
+
+
+
+      // collapse edges edges based upon the predicate implemented by EdgeMerger.
+      size_t collapseEdges(meshset_t *mesh,
+                           const EdgeMerger &merger) {
+        face_rtree_t *tree = face_rtree_t::construct_STR(mesh->faceBegin(), mesh->faceEnd(), 4, 4);
+
+        size_t n_mods = 0;
+
+        std::vector<EdgeInfo *> edge_heap;
+        std::unordered_map<vertex_t *, std::set<EdgeInfo *> > vert_to_edges;
+
+        edge_heap.reserve(edge_info.size());
+
+        for (edge_info_map_t::iterator i = edge_info.begin();
+             i != edge_info.end();
+             ++i) {
+          EdgeInfo *e = (*i).second;
+
+          vert_to_edges[e->edge->v1()].insert(e);
+          vert_to_edges[e->edge->v2()].insert(e);
+
+          if (merger.canMerge(e)) {
+            edge_heap.push_back(e);
+          } else {
+            e->heap_idx = ~0U;
+          }
+        }
+
+        carve::heap::make_heap(edge_heap.begin(),
+                               edge_heap.end(),
+                               merger.priority(),
+                               EdgeInfo::NotifyPos());
+
+        while (edge_heap.size()) {
+//           std::cerr << "test" << std::endl;
+//           for (size_t m = 0; m < mesh->meshes.size(); ++m) {
+//             for (size_t f = 0; f < mesh->meshes[m]->faces.size(); ++f) {
+//               if (mesh->meshes[m]->faces[f]->edge) mesh->meshes[m]->faces[f]->edge->validateLoop();
+//             }
+//           }
+          carve::heap::pop_heap(edge_heap.begin(),
+                                edge_heap.end(),
+                                merger.priority(),
+                                EdgeInfo::NotifyPos());
+          EdgeInfo *e = edge_heap.back();
+          edge_heap.pop_back();
+          e->heap_idx = ~0U;
+
+          edge_t *edge = e->edge;
+          vertex_t *v1 = edge->v1();
+          vertex_t *v2 = edge->v2();
+
+          std::set<face_t *> affected_faces;
+          for (std::set<EdgeInfo *>::iterator f = vert_to_edges[v1].begin();
+               f != vert_to_edges[v1].end();
+               ++f) {
+            affected_faces.insert((*f)->edge->face);
+            affected_faces.insert((*f)->edge->rev->face);
+          }
+          for (std::set<EdgeInfo *>::iterator f = vert_to_edges[v2].begin();
+               f != vert_to_edges[v2].end();
+               ++f) {
+            affected_faces.insert((*f)->edge->face);
+            affected_faces.insert((*f)->edge->rev->face);
+          }
+
+          std::vector<EdgeInfo *> edges_to_merge;
+          std::vector<EdgeInfo *> v1_incident;
+          std::vector<EdgeInfo *> v2_incident;
+
+          std::set_intersection(vert_to_edges[v1].begin(), vert_to_edges[v1].end(),
+                                vert_to_edges[v2].begin(), vert_to_edges[v2].end(),
+                                std::back_inserter(edges_to_merge));
+
+          CARVE_ASSERT(edges_to_merge.size() > 0);
+
+          std::set_difference(vert_to_edges[v1].begin(), vert_to_edges[v1].end(),
+                              edges_to_merge.begin(), edges_to_merge.end(),
+                              std::back_inserter(v1_incident));
+          std::set_difference(vert_to_edges[v2].begin(), vert_to_edges[v2].end(),
+                              edges_to_merge.begin(), edges_to_merge.end(),
+                              std::back_inserter(v2_incident));
+
+          vector_t aabb_min, aabb_max;
+          assign_op(aabb_min, v1->v, v2->v, carve::util::min_functor());
+          assign_op(aabb_max, v1->v, v2->v, carve::util::max_functor());
+          
+          for (size_t i = 0; i < v1_incident.size(); ++i) {
+            assign_op(aabb_min, aabb_min, v1_incident[i]->edge->v1()->v, carve::util::min_functor());
+            assign_op(aabb_max, aabb_max, v1_incident[i]->edge->v1()->v, carve::util::max_functor());
+            assign_op(aabb_min, aabb_min, v1_incident[i]->edge->v2()->v, carve::util::min_functor());
+            assign_op(aabb_max, aabb_max, v1_incident[i]->edge->v2()->v, carve::util::max_functor());
+          }
+
+          for (size_t i = 0; i < v2_incident.size(); ++i) {
+            assign_op(aabb_min, aabb_min, v2_incident[i]->edge->v1()->v, carve::util::min_functor());
+            assign_op(aabb_max, aabb_max, v2_incident[i]->edge->v1()->v, carve::util::max_functor());
+            assign_op(aabb_min, aabb_min, v2_incident[i]->edge->v2()->v, carve::util::min_functor());
+            assign_op(aabb_max, aabb_max, v2_incident[i]->edge->v2()->v, carve::util::max_functor());
+          }
+
+          aabb_t aabb;
+          aabb.fit(aabb_min, aabb_max);
+
+          std::vector<face_t *> near_faces;
+          tree->search(aabb, std::back_inserter(near_faces));
+
+          double frac = 0.5; // compute this based upon v1_incident and v2_incident?
+          vector_t merge = frac * v1->v + (1 - frac) * v2->v;
+
+          int i1 = countIntersectionPairs(affected_faces.begin(), affected_faces.end(),
+                                          near_faces.begin(), near_faces.end(),
+                                          NULL, NULL, merge);
+          int i2 = countIntersectionPairs(affected_faces.begin(), affected_faces.end(),
+                                          near_faces.begin(), near_faces.end(),
+                                          v1, v2, merge);
+          if (i2 != i1) {
+            std::cerr << "near faces: " << near_faces.size() << " affected faces: " << affected_faces.size() << std::endl;
+            std::cerr << "merge delta[ints] = " << i2 - i1 << " pre: " << i1 << " post: " << i2 << std::endl;
+            if (i2 > i1) continue;
+          }
+
+          std::cerr << "collapse " << e << std::endl;
+
+          v2->v = merge;
+          ++n_mods;
+
+          for (size_t i = 0; i < v1_incident.size(); ++i) {
+            if (v1_incident[i]->edge->vert == v1) {
+              v1_incident[i]->edge->vert = v2;
+            }
+          }
+
+          for (size_t i = 0; i < v1_incident.size(); ++i) {
+            updateEdgeMergeHeap(edge_heap, v1_incident[i], merger);
+          }
+
+          for (size_t i = 0; i < v2_incident.size(); ++i) {
+            updateEdgeMergeHeap(edge_heap, v2_incident[i], merger);
+          }
+
+          vert_to_edges[v2].insert(vert_to_edges[v1].begin(), vert_to_edges[v1].end());
+          vert_to_edges.erase(v1);
+
+          for (size_t i = 0; i < edges_to_merge.size(); ++i) {
+            EdgeInfo *e = edges_to_merge[i];
+
+            removeFromEdgeMergeHeap(edge_heap, e, merger);
+            edge_info.erase(e->edge);
+
+            vert_to_edges[v1].erase(e);
+            vert_to_edges[v2].erase(e);
+
+            face_t *f1 = e->edge->face;
+
+            e->edge->removeHalfEdge();
+
+            if (f1->n_edges == 2) {
+              edge_t *e1 = f1->edge;
+              edge_t *e2 = f1->edge->next;
+              if (e1->rev) e1->rev->rev = e2->rev;
+              if (e2->rev) e2->rev->rev = e1->rev;
+              EdgeInfo *e1i = edge_info[e1];
+              EdgeInfo *e2i = edge_info[e2];
+              CARVE_ASSERT(e1i != NULL);
+              CARVE_ASSERT(e2i != NULL);
+              vert_to_edges[e1->v1()].erase(e1i);
+              vert_to_edges[e1->v2()].erase(e1i);
+              vert_to_edges[e2->v1()].erase(e2i);
+              vert_to_edges[e2->v2()].erase(e2i);
+              removeFromEdgeMergeHeap(edge_heap, e1i, merger);
+              removeFromEdgeMergeHeap(edge_heap, e2i, merger);
+              edge_info.erase(e1);
+              edge_info.erase(e2);
+              f1->clearEdges();
+              tree->remove(f1, aabb);
+
+              delete e1i;
+              delete e2i;
+            }
+            delete e;
+          }
+
+          tree->updateExtents(aabb);
+        }
+
+        delete tree;
+
+        return n_mods;
+      }
+
+
+
+      size_t mergeCoplanarFaces(mesh_t *mesh, double min_normal_angle) {
+        std::unordered_set<edge_t *> coplanar_face_edges;
+        double min_dp = cos(min_normal_angle);
+        size_t n_merge = 0;
+
+        for (size_t i = 0; i < mesh->closed_edges.size(); ++i) {
+          edge_t *e = mesh->closed_edges[i];
+          face_t *f1 = e->face;
+          face_t *f2 = e->rev->face;
+
+          if (carve::geom::dot(f1->plane.N, f2->plane.N) < min_dp) {
+            continue;
+          }
+
+          coplanar_face_edges.insert(std::min(e, e->rev));
+        }
+
+        while (coplanar_face_edges.size()) {
+          edge_t *edge = *coplanar_face_edges.begin();
+          if (edge->face == edge->rev->face) {
+            coplanar_face_edges.erase(edge);
+            continue;
+          }
+
+          edge_t *removed = edge->mergeFaces();
+          if (removed == NULL) {
+            coplanar_face_edges.erase(edge);
+            ++n_merge;
+          } else {
+            edge_t *e = removed;
+            do {
+              edge_t *n = e->next;
+              coplanar_face_edges.erase(std::min(e, e->rev));
+              delete e->rev;
+              delete e;
+              e = n;
+            } while (e != removed);
+          }
+        }
+        return n_merge;
+      }
+
+
+
+      uint8_t affected_axes(const face_t *face) {
+        uint8_t r = 0;
+        if (fabs(carve::geom::dot(face->plane.N, carve::geom::VECTOR(1,0,0))) > 0.001) r |= 1;
+        if (fabs(carve::geom::dot(face->plane.N, carve::geom::VECTOR(0,1,0))) > 0.001) r |= 2;
+        if (fabs(carve::geom::dot(face->plane.N, carve::geom::VECTOR(0,0,1))) > 0.001) r |= 4;
+        return r;
+      }
+
+
+
+      double median(std::vector<double> &v) {
+        if (v.size() & 1) {
+          size_t N = v.size() / 2 + 1;
+          std::nth_element(v.begin(), v.begin() + N, v.end());
+          return v[N];
+        } else {
+          size_t N = v.size() / 2;
+          std::nth_element(v.begin(), v.begin() + N, v.end());
+          return (v[N] + *std::min_element(v.begin() + N + 1, v.end())) / 2.0;
+        }
+      }
+
+
+
+      double harmonicmean(const std::vector<double> &v) {
+        double m = 0.0;
+        for (size_t i = 0; i < v.size(); ++i) {
+          m *= v[i];
+        }
+        return pow(m, 1.0 / v.size());
+      }
+
+
+
+      double mean(const std::vector<double> &v) {
+        double m = 0.0;
+        for (size_t i = 0; i < v.size(); ++i) {
+          m += v[i];
+        }
+        return m / v.size();
+      }
+
+
+
+      template<typename iter_t>
+      void snapFaces(iter_t begin, iter_t end, double grid, int axis) {
+        std::set<vertex_t *> vertices;
+        for (iter_t i = begin; i != end; ++i) {
+          face_t *face = *i;
+          edge_t *edge = face->edge;
+          do {
+            vertices.insert(edge->vert);
+            edge = edge->next;
+          } while (edge != face->edge);
+        }
+
+        std::vector<double> pos;
+        pos.reserve(vertices.size());
+        for (std::set<vertex_t *>::iterator i = vertices.begin(); i != vertices.end(); ++i) {
+          pos.push_back((*i)->v.v[axis]);
+        }
+
+        double med = median(pos);
+
+        double snap_pos = med;
+        if (grid) snap_pos = round(snap_pos / grid) * grid;
+
+        for (std::set<vertex_t *>::iterator i = vertices.begin(); i != vertices.end(); ++i) {
+          (*i)->v.v[axis] = snap_pos;
+        }
+
+        for (iter_t i = begin; i != end; ++i) {
+          face_t *face = *i;
+          face->recalc();
+          edge_t *edge = face->edge;
+          do {
+            if (edge->rev && edge->rev->face) edge->rev->face->recalc();
+            edge = edge->next;
+          } while (edge != face->edge);
+        }
+      }
+
+      carve::geom::plane<3> quantizePlane(const face_t *face,
+                                          int angle_xy_quantization,
+                                          int angle_z_quantization) {
+        if (!angle_xy_quantization && !angle_z_quantization) {
+          return face->plane;
+        }
+        carve::geom::vector<3> normal = face->plane.N;
+
+        if (angle_z_quantization) {
+          if (normal.x || normal.y) {
+            double a = asin(std::min(std::max(normal.z, 0.0), 1.0));
+            a = round(a * angle_z_quantization / (M_PI * 2)) * (M_PI * 2) / angle_z_quantization;
+            normal.z = sin(a);
+            double s = sqrt((1 - normal.z * normal.z) / (normal.x * normal.x + normal.y * normal.y));
+            normal.x = normal.x * s;
+            normal.y = normal.y * s;
+          }
+        }
+        if (angle_xy_quantization) {
+          if (normal.x || normal.y) {
+            double a = atan2(normal.y, normal.x);
+            a = round(a * angle_xy_quantization / (M_PI * 2)) * (M_PI * 2) / angle_xy_quantization;
+            double s = sqrt(1 - normal.z * normal.z);
+            s = std::min(std::max(s, 0.0), 1.0);
+            normal.x = cos(a) * s;
+            normal.y = sin(a) * s;
+          }
+        }
+
+        std::cerr << "normal = " << normal << std::endl;
+
+        std::vector<double> d_vec;
+        d_vec.reserve(face->nVertices());
+        edge_t *e = face->edge;
+        do {
+          d_vec.push_back(-carve::geom::dot(normal, e->vert->v));
+          e = e->next;
+        } while (e != face->edge);
+
+        return carve::geom::plane<3>(normal, mean(d_vec));
+      }
+
+
+
+      double summedError(const carve::geom::vector<3> &vert, const std::list<carve::geom::plane<3> > &planes) {
+        double d = 0;
+        for (std::list<carve::geom::plane<3> >::const_iterator i = planes.begin(); i != planes.end(); ++i) {
+          d += fabs(carve::geom::distance2(*i, vert));
+        }
+        return d;
+      }
+
+
+
+      double minimize(carve::geom::vector<3> &vert, const std::list<carve::geom::plane<3> > &planes, int axis) {
+        double num = 0.0;
+        double den = 0.0;
+        int a1 = (axis + 1) % 3;
+        int a2 = (axis + 2) % 3;
+        for (std::list<carve::geom::plane<3> >::const_iterator i = planes.begin(); i != planes.end(); ++i) {
+          const carve::geom::vector<3> &N = (*i).N;
+          const double d = (*i).d;
+          den += N.v[axis] * N.v[axis];
+          num -= N.v[axis] * (N.v[a1] * vert.v[a1] + N.v[a2] * vert.v[a2] + d);
+        }
+        if (fabs(den) < 1e-5) return vert.v[axis];
+        return num / den;
+      }
+
+
+
+      size_t cleanFaceEdges(mesh_t *mesh) {
+        size_t n_removed = 0;
+        for (size_t i = 0; i < mesh->faces.size(); ++i) {
+          face_t *face = mesh->faces[i];
+          edge_t *start = face->edge;
+          edge_t *edge = start;
+          do {
+            if (edge->next == edge->rev || edge->prev == edge->rev) {
+              edge = edge->removeEdge();
+              ++n_removed;
+              start = edge->prev;
+            } else {
+              edge = edge->next;
+            }
+          } while (edge != start);
+        }
+        return n_removed;
+      }
+
+
+
+      size_t cleanFaceEdges(meshset_t *mesh) {
+        size_t n_removed = 0;
+        for (size_t i = 0; i < mesh->meshes.size(); ++i) {
+          n_removed += cleanFaceEdges(mesh->meshes[i]);
+        }
+        return n_removed;
+      }
+
+
+
+      void removeRemnantFaces(mesh_t *mesh) {
+        size_t n = 0;
+        for (size_t i = 0; i < mesh->faces.size(); ++i) {
+          if (mesh->faces[i]->nEdges() == 0) {
+            delete mesh->faces[i];
+          } else {
+            mesh->faces[n++] = mesh->faces[i];
+          }
+        }
+        mesh->faces.resize(n);
+      }
+
+
+
+      void removeRemnantFaces(meshset_t *mesh) {
+        for (size_t i = 0; i < mesh->meshes.size(); ++i) {
+          removeRemnantFaces(mesh->meshes[i]);
+        }
+      }
+
+
+
+      edge_t *removeFin(edge_t *e) {
+        // e and e->next are shared with the same reverse triangle.
+        edge_t *e1 = e->prev;
+        edge_t *e2 = e->rev->next;
+        CARVE_ASSERT(e1->v2() == e2->v1());
+        CARVE_ASSERT(e2->v2() == e1->v1());
+
+        CARVE_ASSERT(e1->rev != e2 && e2->rev != e1);
+
+        edge_t *e1r = e1->rev;
+        edge_t *e2r = e2->rev;
+        if (e1r) e1r->rev = e2r;
+        if (e2r) e2r->rev = e1r;
+
+        face_t *f1 = e1->face;
+        face_t *f2 = e2->face;
+        f1->clearEdges();
+        f2->clearEdges();
+
+        return e1r;
+      }
+
+      size_t removeFin(face_t *face) {
+        if (face->edge == NULL || face->nEdges() != 3) return 0;
+        edge_t *e = face->edge;
+        do {
+          if (e->rev != NULL) {
+            face_t *revface = e->rev->face;
+            if (revface->nEdges() == 3) {
+              if (e->next->rev && e->next->rev->face == revface) {
+                if (e->next->next->rev && e->next->next->rev->face == revface) {
+                  // isolated tripair
+                  face->clearEdges();
+                  revface->clearEdges();
+                  return 1;
+                }
+                // fin
+                edge_t *spliced_edge = removeFin(e);
+                return 1 + removeFin(spliced_edge->face);
+              }
+            }
+          }
+          e = e->next;
+        } while (e != face->edge);
+        return 0;
+      }
+
+
+
+    public:
+      // Merge adjacent coplanar faces (where coplanar is determined
+      // by dot-product >= cos(min_normal_angle)).
+      size_t mergeCoplanarFaces(meshset_t *meshset, double min_normal_angle) {
+        size_t n_removed = 0;
+        for (size_t i = 0; i < meshset->meshes.size(); ++i) {
+          n_removed += mergeCoplanarFaces(meshset->meshes[i], min_normal_angle);
+          removeRemnantFaces(meshset->meshes[i]);
+          cleanFaceEdges(meshset->meshes[i]);
+          meshset->meshes[i]->cacheEdges();
+        }
+        return n_removed;
+      }
+
+      size_t improveMesh_conservative(meshset_t *meshset) {
+        initEdgeInfo(meshset);
+        size_t modifications = flipEdges(meshset, FlippableConservative());
+        clearEdgeInfo();
+        return modifications;
+      }
+
+
+
+      size_t improveMesh(meshset_t *meshset,
+                         double min_colinearity,
+                         double min_delta_v,
+                         double min_normal_angle) {
+        initEdgeInfo(meshset);
+        size_t modifications = flipEdges(meshset, Flippable(min_colinearity, min_delta_v, min_normal_angle));
+        clearEdgeInfo();
+        return modifications;
+      }
+
+
+
+      size_t eliminateShortEdges(meshset_t *meshset,
+                                 double min_length) {
+        initEdgeInfo(meshset);
+        size_t modifications = collapseEdges(meshset, EdgeMerger(min_length));
+        removeRemnantFaces(meshset);
+        clearEdgeInfo();
+        return modifications;
+      }
+
+
+
+      // Snap vertices to grid, aligning almost flat axis-aligned
+      // faces to the axis, and flattening other faces as much as is
+      // possible. Passing a number less than DBL_MIN_EXPONENT (-1021)
+      // turns off snapping to grid (but face alignment is still
+      // performed).
+      void snap(meshset_t *meshset,
+                int log2_grid,
+                int angle_xy_quantization = 0,
+                int angle_z_quantization = 0) {
+        double grid = 0.0;
+        if (log2_grid >= std::numeric_limits<double>::min_exponent) grid = pow(2.0, (double)log2_grid);
+
+        typedef std::unordered_map<face_t *, uint8_t> axis_influence_map_t;
+        axis_influence_map_t axis_influence;
+
+        typedef std::unordered_map<face_t *, std::set<face_t *> > interaction_graph_t;
+        interaction_graph_t interacting_faces;
+
+        for (size_t m = 0; m < meshset->meshes.size(); ++m) {
+          mesh_t *mesh = meshset->meshes[m];
+          for (size_t f = 0; f < mesh->faces.size(); ++f) {
+            face_t *face = mesh->faces[f];
+            axis_influence[face] = affected_axes(face);
+          }
+        }
+
+        std::map<vertex_t *, std::list<carve::geom::plane<3> > > non_axis_vertices;
+        std::unordered_map<vertex_t *, uint8_t> vertex_constraints;
+
+        for (axis_influence_map_t::iterator i = axis_influence.begin(); i != axis_influence.end(); ++i) {
+          face_t *face = (*i).first;
+          uint8_t face_axes = (*i).second;
+          edge_t *edge = face->edge;
+          if (face_axes != 1 && face_axes != 2 && face_axes != 4) {
+            do {
+              non_axis_vertices[edge->vert].push_back(quantizePlane(face,
+                                                                    angle_xy_quantization,
+                                                                    angle_z_quantization));
+              edge = edge->next;
+            } while (edge != face->edge);
+          } else {
+            interacting_faces[face].insert(face);
+            do {
+              vertex_constraints[edge->vert] |= face_axes;
+
+              if (edge->rev && edge->rev->face) {
+                face_t *face2 = edge->rev->face;
+                uint8_t face2_axes = axis_influence[face2];
+                if (face2_axes == face_axes) {
+                  interacting_faces[face].insert(face2);
+                }
+              }
+              edge = edge->next;
+            } while (edge != face->edge);
+          }
+        }
+
+        while (interacting_faces.size()) {
+          std::set<face_t *> face_set;
+          uint8_t axes = 0;
+
+          std::set<face_t *> open;
+          open.insert((*interacting_faces.begin()).first);
+          while (open.size()) {
+            face_t *curr = *open.begin();
+            open.erase(open.begin());
+            face_set.insert(curr);
+            axes |= axis_influence[curr];
+            for (interaction_graph_t::data_type::iterator i = interacting_faces[curr].begin(), e = interacting_faces[curr].end(); i != e; ++i) {
+              face_t *f = *i;
+              if (face_set.find(f) != face_set.end()) continue;
+              open.insert(f);
+            }
+          }
+
+          switch (axes) {
+          case 1: snapFaces(face_set.begin(), face_set.end(), grid, 0); break;
+          case 2: snapFaces(face_set.begin(), face_set.end(), grid, 1); break;
+          case 4: snapFaces(face_set.begin(), face_set.end(), grid, 2); break;
+          default: CARVE_FAIL("should not be reached");
+          }
+
+          for (std::set<face_t *>::iterator i = face_set.begin(); i != face_set.end(); ++i) {
+            interacting_faces.erase((*i));
+          }
+        }
+
+        for (std::map<vertex_t *, std::list<carve::geom::plane<3> > >::iterator i = non_axis_vertices.begin(); i != non_axis_vertices.end(); ++i) {
+          vertex_t *vert = (*i).first;
+          std::list<carve::geom::plane<3> > &planes = (*i).second;
+          uint8_t constraint = vertex_constraints[vert];
+
+          if (constraint == 7) continue;
+
+          double d = summedError(vert->v, planes);
+          for (size_t N = 0; ; N = (N+1) % 3) {
+            if (constraint & (1 << N)) continue;
+            vert->v[N] = minimize(vert->v, planes, N);
+            double d_next = summedError(vert->v, planes);
+            if (d - d_next < 1e-20) break;
+            d = d_next;
+          }
+
+          if (grid) {
+            carve::geom::vector<3> v_best = vert->v;
+            double d_best = 0.0;
+            
+            for (size_t axes = 0; axes < 8; ++axes) {
+              carve::geom::vector<3> v = vert->v;
+              for (size_t N = 0; N < 3; ++N) {
+                if (constraint & (1 << N)) continue;
+                if (axes & (1<<N)) {
+                  v.v[N] = ceil(v.v[N] / grid) * grid;
+                } else {
+                  v.v[N] = floor(v.v[N] / grid) * grid;
+                }
+              }
+              double d = summedError(v, planes);
+              if (axes == 0 || d < d_best) {
+                v_best = v;
+                d_best = d;
+              }
+            }
+
+            vert->v = v_best;
+          }
+        }
+      }
+
+
+
+      size_t simplify(meshset_t *meshset,
+                      double min_colinearity,
+                      double min_delta_v,
+                      double min_normal_angle,
+                      double min_length) {
+        size_t modifications = 0;
+        size_t n, n_flip, n_merge;
+
+        initEdgeInfo(meshset);
+
+        std::cerr << "initial merge" << std::endl;
+        modifications = collapseEdges(meshset, EdgeMerger(0.0));
+        removeRemnantFaces(meshset);
+
+        do {
+          n_flip = n_merge = 0;
+          // std::cerr << "flip colinear pairs";
+          // n = flipEdges(meshset, FlippableColinearPair());
+          // std::cerr << " " << n << std::endl;
+          // n_flip = n;
+
+          std::cerr << "flip conservative";
+          n = flipEdges(meshset, FlippableConservative());
+          std::cerr << " " << n << std::endl;
+          n_flip += n;
+
+          std::cerr << "flip";
+          n = flipEdges(meshset, Flippable(min_colinearity, min_delta_v, min_normal_angle));
+          std::cerr << " " << n << std::endl;
+          n_flip += n;
+
+          std::cerr << "merge";
+          n = collapseEdges(meshset, EdgeMerger(min_length));
+          removeRemnantFaces(meshset);
+          std::cerr << " " << n << std::endl;
+          n_merge = n;
+
+          modifications += n_flip + n_merge;
+          std::cerr << "stats:" << n_flip << " " << n_merge << std::endl;
+        } while (n_flip || n_merge);
+
+        clearEdgeInfo();
+
+        for (size_t i = 0; i < meshset->meshes.size(); ++i) {
+          meshset->meshes[i]->cacheEdges();
+        }
+
+        return modifications;
+      }
+
+      
+      
+      size_t removeFins(mesh_t *mesh) {
+        size_t n_removed = 0;
+        for (size_t i = 0; i < mesh->faces.size(); ++i) {
+          n_removed += removeFin(mesh->faces[i]);
+        }
+        if (n_removed) removeRemnantFaces(mesh);
+        return n_removed;
+      }
+
+
+
+      size_t removeFins(meshset_t *meshset) {
+        size_t n_removed = 0;
+        for (size_t i = 0; i < meshset->meshes.size(); ++i) {
+          n_removed += removeFins(meshset->meshes[i]);
+        }
+        return n_removed;
+      }
+
+
+
+      size_t removeLowVolumeManifolds(meshset_t *meshset, double min_abs_volume) {
+        size_t n_removed;
+        for (size_t i = 0; i < meshset->meshes.size(); ++i) {
+          if (fabs(meshset->meshes[i]->volume()) < min_abs_volume) {
+            delete meshset->meshes[i];
+            meshset->meshes[i] = NULL;
+            ++n_removed;
+          }
+        }
+        meshset->meshes.erase(std::remove_if(meshset->meshes.begin(),
+                                             meshset->meshes.end(),
+                                             std::bind2nd(std::equal_to<mesh_t *>(), (mesh_t *)NULL)),
+                              meshset->meshes.end());
+        return n_removed;
+      }
+
+      struct point_enumerator_t {
+        struct heapval_t {
+          double dist;
+          vector_t pt;
+          heapval_t(double _dist, vector_t _pt) : dist(_dist), pt(_pt) {
+          }
+          heapval_t() {}
+          bool operator==(const heapval_t &other) const { return dist == other.dist && pt == other.pt; }
+          bool operator<(const heapval_t &other) const { return dist > other.dist || (dist == other.dist && pt > other.pt); }
+        };
+
+        vector_t origin;
+        double rounding_fac;
+        heapval_t last;
+        std::vector<heapval_t> heap;
+
+        point_enumerator_t(vector_t _origin, int _base, int _n_dp) : origin(_origin), rounding_fac(pow(_base, _n_dp)), last(-1.0, _origin), heap() {
+          for (size_t i = 0; i < (1 << 3); ++i) {
+            vector_t t = origin;
+            for (size_t j = 0; j < 3; ++j) {
+              if (i & (1U << j)) {
+                t[j] = ceil(t[j] * rounding_fac) / rounding_fac;
+              } else {
+                t[j] = floor(t[j] * rounding_fac) / rounding_fac;
+              }
+            }
+            heap.push_back(heapval_t(carve::geom::distance2(origin, t), t));
+          }
+          std::make_heap(heap.begin(), heap.end());
+        }
+
+        vector_t next() {
+          heapval_t curr;
+          do {
+            CARVE_ASSERT(heap.size());
+            std::pop_heap(heap.begin(), heap.end());
+            curr = heap.back();
+            heap.pop_back();
+          } while (curr == last);
+
+          vector_t t;
+
+          for (int dx = -1; dx <= +1; ++dx) {
+            t.x = floor(curr.pt.x * rounding_fac + dx) / rounding_fac;
+            for (int dy = -1; dy <= +1; ++dy) {
+              t.y = floor(curr.pt.y * rounding_fac + dy) / rounding_fac;
+              for (int dz = -1; dz <= +1; ++dz) {
+                t.z = floor(curr.pt.z * rounding_fac + dz) / rounding_fac;
+                heapval_t h2(carve::geom::distance2(origin, t), t);
+                if (h2 < curr) {
+                  heap.push_back(h2);
+                  std::push_heap(heap.begin(), heap.end());
+                }
+              }
+            }
+          }
+          last = curr;
+          return curr.pt;
+        }
+      };
+
+      struct quantization_info_t {
+        point_enumerator_t *pt;
+        std::set<face_t *> faces;
+
+        quantization_info_t() : pt(NULL), faces() {
+        }
+
+        ~quantization_info_t() {
+          if (pt) delete pt;
+        }
+
+        aabb_t getAABB() const {
+          std::set<face_t *>::iterator i = faces.begin();
+          aabb_t aabb = (*i)->getAABB();
+          while (++i != faces.end()) {
+            aabb.unionAABB((*i)->getAABB());
+          }
+          return aabb;
+        }
+      };
+
+      void selfIntersectionAwareQuantize(meshset_t *meshset, int base, int n_dp) {
+        typedef std::unordered_map<vertex_t *, quantization_info_t> vfsmap_t;
+
+        vfsmap_t vertex_qinfo;
+
+        for (size_t m = 0; m < meshset->meshes.size(); ++m) {
+          mesh_t *mesh = meshset->meshes[m];
+          for (size_t f = 0; f < mesh->faces.size(); ++f) {
+            face_t *face = mesh->faces[f];
+            edge_t *e = face->edge;
+            do {
+              vertex_qinfo[e->vert].faces.insert(face);
+              e = e->next;
+            } while (e != face->edge);
+          }
+        }
+
+        face_rtree_t *tree = face_rtree_t::construct_STR(meshset->faceBegin(), meshset->faceEnd(), 4, 4);
+
+        for (vfsmap_t::iterator i = vertex_qinfo.begin(); i != vertex_qinfo.end(); ++i) {
+          (*i).second.pt = new point_enumerator_t((*i).first->v, base, n_dp);
+        }
+
+        while (vertex_qinfo.size()) {
+          std::vector<vertex_t *> quantized;
+
+          std::cerr << "vertex_qinfo.size() == " << vertex_qinfo.size() << std::endl;
+
+          for (vfsmap_t::iterator i = vertex_qinfo.begin(); i != vertex_qinfo.end(); ++i) {
+            vertex_t *vert = (*i).first;
+            quantization_info_t &qi = (*i).second;
+            vector_t q_pt = qi.pt->next();
+            aabb_t aabb = qi.getAABB();
+            aabb.unionAABB(aabb_t(q_pt));
+
+            std::vector<face_t *> overlapping;
+            tree->search(aabb, std::back_inserter(overlapping));
+
+
+            int n_intersections = countIntersectionPairs(qi.faces.begin(), qi.faces.end(),
+                                                         overlapping.begin(), overlapping.end(),
+                                                         vert, NULL, q_pt);
+
+            if (n_intersections == 0) {
+              vert->v = q_pt;
+              quantized.push_back((*i).first);
+              tree->updateExtents(aabb);
+            }
+          }
+          for (size_t i = 0; i < quantized.size(); ++i) {
+            vertex_qinfo.erase(quantized[i]);
+          }
+
+          if (!quantized.size()) break;
+        }
+      }
+
+
+    };
+  }
+}
diff --git a/extern/carve/include/carve/octree_decl.hpp b/extern/carve/include/carve/octree_decl.hpp
new file mode 100644
index 00000000000..a7e3ff5c77a
--- /dev/null
+++ b/extern/carve/include/carve/octree_decl.hpp
@@ -0,0 +1,193 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom3d.hpp>
+#include <carve/aabb.hpp>
+
+#include <carve/polyhedron_base.hpp>
+
+namespace carve {
+
+  namespace csg {
+
+    const double SLACK_FACTOR=1.0009765625;
+    const unsigned FACE_SPLIT_THRESHOLD=50U;
+    const unsigned EDGE_SPLIT_THRESHOLD=50U;
+    const unsigned POINT_SPLIT_THRESHOLD=20U;
+    const unsigned MAX_SPLIT_DEPTH=32;
+
+    class Octree {
+
+    public:
+      class Node {
+      private:
+        Node(const Node &node); // undefined.
+        Node &operator=(const Node &node); // undefined.
+
+      public:
+        Node *parent;
+        Node *children[8];
+        bool is_leaf;
+
+        carve::geom3d::Vector min;
+        carve::geom3d::Vector max;
+
+        std::vector<const carve::poly::Geometry<3>::face_t *> faces;
+        std::vector<const carve::poly::Geometry<3>::edge_t *> edges;
+        std::vector<const carve::poly::Geometry<3>::vertex_t *> vertices;
+
+        carve::geom3d::AABB aabb;
+
+        Node();
+
+        Node(const carve::geom3d::Vector &newMin, const carve::geom3d::Vector &newMax);
+        Node(Node *p, double x1, double y1, double z1, double x2, double y2, double z2);
+
+        ~Node();
+
+        bool mightContain(const carve::poly::Geometry<3>::face_t &face);
+        bool mightContain(const carve::poly::Geometry<3>::edge_t &edge);
+        bool mightContain(const carve::poly::Geometry<3>::vertex_t &p);
+        bool hasChildren();
+        bool hasGeometry();
+
+        template <class T>
+        void putInside(const T &input, Node *child, T &output);
+
+        bool split();
+      };
+
+
+
+      Node *root;
+
+
+
+      struct no_filter {
+        bool operator()(const carve::poly::Geometry<3>::edge_t *) { return true; }
+        bool operator()(const carve::poly::Geometry<3>::face_t *) { return true; }
+      };
+
+
+
+      Octree();
+
+      ~Octree();
+
+
+
+      void setBounds(const carve::geom3d::Vector &min, const carve::geom3d::Vector &max);
+      void setBounds(carve::geom3d::AABB aabb);
+
+
+
+      void addEdges(const std::vector<carve::poly::Geometry<3>::edge_t > &edges);
+      void addFaces(const std::vector<carve::poly::Geometry<3>::face_t > &faces);
+      void addVertices(const std::vector<const carve::poly::Geometry<3>::vertex_t *> &vertices);
+
+
+
+      static carve::geom3d::AABB makeAABB(const Node *node);
+
+
+
+      void doFindEdges(const carve::geom::aabb<3> &aabb,
+                       Node *node,
+                       std::vector<const carve::poly::Geometry<3>::edge_t *> &out,
+                       unsigned depth) const;
+      void doFindEdges(const carve::geom3d::LineSegment &l,
+                       Node *node,
+                       std::vector<const carve::poly::Geometry<3>::edge_t *> &out,
+                       unsigned depth) const;
+      void doFindEdges(const carve::geom3d::Vector &v,
+                       Node *node,
+                       std::vector<const carve::poly::Geometry<3>::edge_t *> &out,
+                       unsigned depth) const;
+      void doFindFaces(const carve::geom::aabb<3> &aabb,
+                       Node *node,
+                       std::vector<const carve::poly::Geometry<3>::face_t *> &out,
+                       unsigned depth) const;
+      void doFindFaces(const carve::geom3d::LineSegment &l,
+                       Node *node,
+                       std::vector<const carve::poly::Geometry<3>::face_t *> &out,
+                       unsigned depth) const;
+
+
+
+      void doFindVerticesAllowDupes(const carve::geom3d::Vector &v,
+                                    Node *node,
+                                    std::vector<const carve::poly::Geometry<3>::vertex_t *> &out,
+                                    unsigned depth) const;
+
+      void findVerticesNearAllowDupes(const carve::geom3d::Vector &v,
+                                      std::vector<const carve::poly::Geometry<3>::vertex_t *> &out) const;
+
+
+
+      template<typename filter_t>
+      void doFindEdges(const carve::poly::Geometry<3>::face_t &f, Node *node,
+                       std::vector<const carve::poly::Geometry<3>::edge_t *> &out,
+                       unsigned depth,
+                       filter_t filter) const;
+
+      template<typename filter_t>
+      void findEdgesNear(const carve::poly::Geometry<3>::face_t &f,
+                         std::vector<const carve::poly::Geometry<3>::edge_t *> &out,
+                         filter_t filter) const;
+
+      void findEdgesNear(const carve::poly::Geometry<3>::face_t &f,
+                         std::vector<const carve::poly::Geometry<3>::edge_t *> &out) const {
+        return findEdgesNear(f, out, no_filter());
+      }
+
+
+
+      void findEdgesNear(const carve::geom::aabb<3> &aabb, std::vector<const carve::poly::Geometry<3>::edge_t *> &out) const;
+      void findEdgesNear(const carve::geom3d::LineSegment &l, std::vector<const carve::poly::Geometry<3>::edge_t *> &out) const;
+      void findEdgesNear(const carve::poly::Geometry<3>::edge_t &e, std::vector<const carve::poly::Geometry<3>::edge_t *> &out) const;
+      void findEdgesNear(const carve::geom3d::Vector &v, std::vector<const carve::poly::Geometry<3>::edge_t *> &out) const;
+
+
+
+      void findFacesNear(const carve::geom::aabb<3> &aabb, std::vector<const carve::poly::Geometry<3>::face_t *> &out) const;
+      void findFacesNear(const carve::geom3d::LineSegment &l, std::vector<const carve::poly::Geometry<3>::face_t *> &out) const;
+      void findFacesNear(const carve::poly::Geometry<3>::edge_t &e, std::vector<const carve::poly::Geometry<3>::face_t *> &out) const;
+
+
+
+      static void doSplit(int maxSplit, Node *node);
+
+
+
+      template <typename FUNC>
+      void doIterate(int level, Node *node, const FUNC &f) const;
+
+      template <typename FUNC>
+      void iterateNodes(const FUNC &f) const;
+
+
+
+      void splitTree();
+
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/octree_impl.hpp b/extern/carve/include/carve/octree_impl.hpp
new file mode 100644
index 00000000000..5eadb1543a0
--- /dev/null
+++ b/extern/carve/include/carve/octree_impl.hpp
@@ -0,0 +1,79 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+namespace carve {
+  namespace csg {
+    template<typename filter_t>
+    void Octree::doFindEdges(const carve::poly::Geometry<3>::face_t &f,
+                             Node *node,
+                             std::vector<const carve::poly::Geometry<3>::edge_t *> &out,
+                             unsigned depth,
+                             filter_t filter) const {
+      if (node == NULL) {
+        return;
+      }
+
+      if (node->aabb.intersects(f.aabb) && node->aabb.intersects(f.plane_eqn)) {
+        if (node->hasChildren()) {
+          for (int i = 0; i < 8; ++i) {
+            doFindEdges(f, node->children[i], out, depth + 1, filter);
+          }
+        } else {
+          if (depth < MAX_SPLIT_DEPTH && node->edges.size() > EDGE_SPLIT_THRESHOLD) {
+            if (!node->split()) {
+              for (int i = 0; i < 8; ++i) {
+                doFindEdges(f, node->children[i], out, depth + 1, filter);
+              }
+              return;
+            }
+          }
+          for (std::vector<const carve::poly::Geometry<3>::edge_t*>::const_iterator it = node->edges.begin(), e = node->edges.end(); it != e; ++it) {
+            if ((*it)->tag_once()) {
+              if (filter(*it)) {
+                out.push_back(*it);
+              }
+            }
+          }
+        }
+      }
+    }
+
+    template<typename filter_t>
+    void Octree::findEdgesNear(const carve::poly::Geometry<3>::face_t &f, std::vector<const carve::poly::Geometry<3>::edge_t *> &out, filter_t filter) const {
+      tagable::tag_begin();
+      doFindEdges(f, root, out, 0, filter);
+    }
+
+    template <typename func_t>
+    void Octree::doIterate(int level, Node *node, const func_t &f) const{
+      f(level, node);
+      if (node->hasChildren()) {
+        for (int i = 0; i < 8; ++i) {
+          doIterate(level + 1, node->children[i], f);
+        }
+      }
+    }
+
+    template <typename func_t>
+    void Octree::iterateNodes(const func_t &f) const {
+      doIterate(0, root, f);
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/pointset.hpp b/extern/carve/include/carve/pointset.hpp
new file mode 100644
index 00000000000..c635ce47f2f
--- /dev/null
+++ b/extern/carve/include/carve/pointset.hpp
@@ -0,0 +1,24 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/pointset_decl.hpp>
+#include <carve/pointset_impl.hpp>
+#include <carve/pointset_iter.hpp>
diff --git a/extern/carve/include/carve/pointset_decl.hpp b/extern/carve/include/carve/pointset_decl.hpp
new file mode 100644
index 00000000000..d09f9e0e724
--- /dev/null
+++ b/extern/carve/include/carve/pointset_decl.hpp
@@ -0,0 +1,61 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#include <iterator>
+#include <list>
+#include <iterator>
+#include <limits>
+
+#include <carve/carve.hpp>
+#include <carve/tag.hpp>
+#include <carve/geom.hpp>
+#include <carve/kd_node.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/aabb.hpp>
+
+namespace carve {
+  namespace point {
+
+    struct Vertex : public tagable {
+      carve::geom3d::Vector v;
+    };
+
+
+
+    struct vec_adapt_vertex_ptr {
+      const carve::geom3d::Vector &operator()(const Vertex * const &v) { return v->v; }
+      carve::geom3d::Vector &operator()(Vertex *&v) { return v->v; }
+    };
+
+
+
+    struct PointSet {
+      std::vector<Vertex> vertices;
+      carve::geom3d::AABB aabb;
+
+      PointSet(const std::vector<carve::geom3d::Vector> &points);
+      PointSet() {
+      }
+
+      void sortVertices(const carve::geom3d::Vector &axis);
+
+      size_t vertexToIndex_fast(const Vertex *v) const;
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/pointset_impl.hpp b/extern/carve/include/carve/pointset_impl.hpp
new file mode 100644
index 00000000000..71b5f281c0f
--- /dev/null
+++ b/extern/carve/include/carve/pointset_impl.hpp
@@ -0,0 +1,36 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#include <vector>
+
+#include <carve/carve.hpp>
+#include <carve/tag.hpp>
+#include <carve/geom.hpp>
+#include <carve/kd_node.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/aabb.hpp>
+
+namespace carve {
+  namespace point {
+
+    inline size_t PointSet::vertexToIndex_fast(const Vertex *v) const {
+      return v - &vertices[0];
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/pointset_iter.hpp b/extern/carve/include/carve/pointset_iter.hpp
new file mode 100644
index 00000000000..13cf66e4584
--- /dev/null
+++ b/extern/carve/include/carve/pointset_iter.hpp
@@ -0,0 +1,18 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
diff --git a/extern/carve/include/carve/poly.hpp b/extern/carve/include/carve/poly.hpp
new file mode 100644
index 00000000000..913d0600aca
--- /dev/null
+++ b/extern/carve/include/carve/poly.hpp
@@ -0,0 +1,24 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/poly_decl.hpp>
+
+#include <carve/poly_impl.hpp>
diff --git a/extern/carve/include/carve/poly_decl.hpp b/extern/carve/include/carve/poly_decl.hpp
new file mode 100644
index 00000000000..fe550082dbb
--- /dev/null
+++ b/extern/carve/include/carve/poly_decl.hpp
@@ -0,0 +1,25 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/vertex_decl.hpp>
+#include <carve/edge_decl.hpp>
+#include <carve/face_decl.hpp>
+#include <carve/polyhedron_decl.hpp>
diff --git a/extern/carve/include/carve/poly_impl.hpp b/extern/carve/include/carve/poly_impl.hpp
new file mode 100644
index 00000000000..db5ae56e6d3
--- /dev/null
+++ b/extern/carve/include/carve/poly_impl.hpp
@@ -0,0 +1,25 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/vertex_impl.hpp>
+#include <carve/edge_impl.hpp>
+#include <carve/face_impl.hpp>
+#include <carve/polyhedron_impl.hpp>
diff --git a/extern/carve/include/carve/polyhedron_base.hpp b/extern/carve/include/carve/polyhedron_base.hpp
new file mode 100644
index 00000000000..f55146f2986
--- /dev/null
+++ b/extern/carve/include/carve/polyhedron_base.hpp
@@ -0,0 +1,149 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom3d.hpp>
+
+#include <carve/vertex_decl.hpp>
+#include <carve/edge_decl.hpp>
+#include <carve/face_decl.hpp>
+
+#include <stddef.h>
+
+namespace carve {
+  namespace poly {
+
+
+
+    struct Object {
+    };
+
+
+
+    template<typename array_t>
+    ptrdiff_t ptrToIndex_fast(const array_t &a, const typename array_t::value_type *v) {
+      return v - &a[0];
+    }
+
+    template<typename array_t>
+    ptrdiff_t ptrToIndex(const array_t &a, const typename array_t::value_type *v) {
+      if (v < &a.front() || v > &a.back()) return -1;
+      return v - &a[0];
+    }
+    
+
+    template<unsigned ndim>
+    struct Geometry : public Object {
+      struct Connectivity {
+      } connectivity;
+    };
+
+
+
+    template<>
+    struct Geometry<2> : public Object {
+      typedef Vertex<2> vertex_t;
+      typedef Edge<2> edge_t;
+
+      struct Connectivity {
+        std::vector<std::vector<const edge_t *> > vertex_to_edge;
+      } connectivity;
+
+      std::vector<vertex_t> vertices;
+      std::vector<edge_t> edges;
+
+      ptrdiff_t vertexToIndex_fast(const vertex_t *v) const { return ptrToIndex_fast(vertices, v); }
+      ptrdiff_t vertexToIndex(const vertex_t *v) const { return ptrToIndex(vertices, v); }
+
+      ptrdiff_t edgeToIndex_fast(const edge_t *e) const { return ptrToIndex_fast(edges, e); }
+      ptrdiff_t edgeToIndex(const edge_t *e) const { return ptrToIndex(edges, e); }
+
+
+
+      // *** connectivity queries
+
+      template<typename T>
+      int vertexToEdges(const vertex_t *v, T result) const;
+    };
+
+
+
+    template<>
+    struct Geometry<3> : public Object {
+      typedef Vertex<3> vertex_t;
+      typedef Edge<3> edge_t;
+      typedef Face<3> face_t;
+
+      struct Connectivity {
+        std::vector<std::vector<const edge_t *> > vertex_to_edge;
+        std::vector<std::vector<const face_t *> > vertex_to_face;
+        std::vector<std::vector<const face_t *> > edge_to_face;
+      } connectivity;
+
+      std::vector<vertex_t> vertices;
+      std::vector<edge_t> edges;
+      std::vector<face_t> faces;
+
+      ptrdiff_t vertexToIndex_fast(const vertex_t *v) const { return ptrToIndex_fast(vertices, v); }
+      ptrdiff_t vertexToIndex(const vertex_t *v) const { return ptrToIndex(vertices, v); }
+
+      ptrdiff_t edgeToIndex_fast(const edge_t *e) const { return ptrToIndex_fast(edges, e); }
+      ptrdiff_t edgeToIndex(const edge_t *e) const { return ptrToIndex(edges, e); }
+
+      ptrdiff_t faceToIndex_fast(const face_t *f) const { return ptrToIndex_fast(faces, f); }
+      ptrdiff_t faceToIndex(const face_t *f) const { return ptrToIndex(faces, f); }
+
+      template<typename order_t>
+      bool orderVertices(order_t order);
+
+      bool orderVertices() { return orderVertices(std::less<vertex_t::vector_t>()); }
+
+
+
+      // *** connectivity queries
+
+      const face_t *connectedFace(const face_t *, const edge_t *) const;
+
+      template<typename T>
+      int _faceNeighbourhood(const face_t *f, int depth, T *result) const;
+
+      template<typename T>
+      int faceNeighbourhood(const face_t *f, int depth, T result) const;
+
+      template<typename T>
+      int faceNeighbourhood(const edge_t *e, int m_id, int depth, T result) const;
+
+      template<typename T>
+      int faceNeighbourhood(const vertex_t *v, int m_id, int depth, T result) const;
+
+      template<typename T>
+      int vertexToEdges(const vertex_t *v, T result) const;
+
+      template<typename T>
+      int edgeToFaces(const edge_t *e, T result) const;
+
+      template<typename T>
+      int vertexToFaces(const vertex_t *v, T result) const;
+    };
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/polyhedron_decl.hpp b/extern/carve/include/carve/polyhedron_decl.hpp
new file mode 100644
index 00000000000..fda2a304691
--- /dev/null
+++ b/extern/carve/include/carve/polyhedron_decl.hpp
@@ -0,0 +1,184 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom3d.hpp>
+
+#include <carve/polyhedron_base.hpp>
+#include <carve/octree_decl.hpp>
+#include <carve/collection_types.hpp>
+
+#include <assert.h>
+#include <list>
+
+
+namespace carve {
+  namespace mesh {
+    template<unsigned ndim>
+    class MeshSet;
+  }
+
+  namespace poly {
+    class Polyhedron;
+  }
+
+  poly::Polyhedron *polyhedronFromMesh(const mesh::MeshSet<3> *, int);
+
+  namespace poly {
+
+    class Polyhedron : public Geometry<3> {
+    private:
+      friend Polyhedron *carve::polyhedronFromMesh(const mesh::MeshSet<3> *, int);
+
+      Polyhedron() {
+      }
+
+      Polyhedron &operator=(const Polyhedron &); // not implemented
+
+      // *** initialization
+
+      bool initSpatialIndex();
+      void initVertexConnectivity();
+      void setFaceAndVertexOwner();
+
+      bool initConnectivity();
+      bool markManifolds();
+      bool calcManifoldEmbedding();
+
+      bool init();
+      void faceRecalc();
+
+      void commonFaceInit(bool _recalc);
+
+    public:
+      static void collectFaceVertices(std::vector<face_t > &faces,
+                                      std::vector<vertex_t > &vertices,
+                                      std::unordered_map<const vertex_t *, const vertex_t *> &vmap);
+
+      static void collectFaceVertices(std::vector<face_t > &faces,
+                                      std::vector<vertex_t > &vertices);
+
+      std::vector<bool> manifold_is_closed;
+      std::vector<bool> manifold_is_negative;
+
+      carve::geom3d::AABB aabb;
+      carve::csg::Octree octree;
+
+
+
+      // *** construction of Polyhedron objects
+
+      Polyhedron(const Polyhedron &);
+
+      // copy a single manifold
+      Polyhedron(const Polyhedron &, int m_id);
+
+      // copy a subset of manifolds
+      Polyhedron(const Polyhedron &, const std::vector<bool> &selected_manifolds);
+
+      Polyhedron(std::vector<face_t > &_faces,
+                 std::vector<vertex_t > &_vertices,
+                 bool _recalc = false);
+
+      Polyhedron(std::vector<face_t > &_faces,
+                 bool _recalc = false);
+
+      Polyhedron(std::list<face_t > &_faces,
+                 bool _recalc = false);
+
+      Polyhedron(const std::vector<carve::geom3d::Vector> &vertices,
+                 int n_faces,
+                 const std::vector<int> &face_indices);
+
+      ~Polyhedron();
+
+
+
+      // *** containment queries
+
+      void testVertexAgainstClosedManifolds(const carve::geom3d::Vector &v,
+                                            std::map<int, PointClass> &result,
+                                            bool ignore_orentation) const;
+
+      PointClass containsVertex(const carve::geom3d::Vector &v,
+                                const face_t **hit_face = NULL,
+                                bool even_odd = false,
+                                int manifold_id = -1) const;
+
+
+
+      // *** locality queries
+
+      void findEdgesNear(const carve::geom::aabb<3> &aabb, std::vector<const edge_t *> &edges) const;
+      void findEdgesNear(const carve::geom3d::LineSegment &l, std::vector<const edge_t *> &edges) const;
+      void findEdgesNear(const carve::geom3d::Vector &v, std::vector<const edge_t *> &edges) const;
+      void findEdgesNear(const face_t &face, std::vector<const edge_t *> &edges) const;
+      void findEdgesNear(const edge_t &edge, std::vector<const edge_t *> &edges) const;
+
+      void findFacesNear(const carve::geom::aabb<3> &aabb, std::vector<const face_t *> &faces) const;
+      void findFacesNear(const carve::geom3d::LineSegment &l, std::vector<const face_t *> &faces) const;
+      void findFacesNear(const edge_t &edge, std::vector<const face_t *> &faces) const;
+
+
+
+      // *** manifold queries
+
+      inline bool vertexOnManifold(const vertex_t *v, int m_id) const;
+      inline bool edgeOnManifold(const edge_t *e, int m_id) const;
+
+      template<typename T>
+      int vertexManifolds(const vertex_t *v, T result) const;
+
+      template<typename T>
+      int edgeManifolds(const edge_t *e, T result) const;
+
+      size_t manifoldCount() const;
+
+      bool hasOpenManifolds() const;
+
+
+
+
+      // *** transformation
+
+      // flip face directions
+      void invertAll();
+      void invert(const std::vector<bool> &selected_manifolds);
+
+      void invert(int m_id);
+      void invert();
+
+      // matrix transform of vertices
+      void transform(const carve::math::Matrix &xform);
+
+      // arbitrary function transform of vertices
+      template<typename T>
+      void transform(const T &xform);
+
+      void print(std::ostream &) const;
+
+      void canonicalize();
+    };
+
+    std::ostream &operator<<(std::ostream &, const Polyhedron &);
+
+  }
+
+}
diff --git a/extern/carve/include/carve/polyhedron_impl.hpp b/extern/carve/include/carve/polyhedron_impl.hpp
new file mode 100644
index 00000000000..06d841c7192
--- /dev/null
+++ b/extern/carve/include/carve/polyhedron_impl.hpp
@@ -0,0 +1,287 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/timing.hpp>
+
+#include <assert.h>
+#include <list>
+
+namespace carve {
+  namespace poly {
+
+
+
+    template<typename order_t>
+    struct VPtrSort {
+      order_t order;
+
+      VPtrSort(const order_t &_order) : order(_order) {}
+      bool operator()(carve::poly::Polyhedron::vertex_t const *a,
+                      carve::poly::Polyhedron::vertex_t const *b) const {
+        return order(a->v, b->v);
+      }
+    };
+
+    template<typename order_t>
+    bool Geometry<3>::orderVertices(order_t order) {
+      static carve::TimingName FUNC_NAME("Geometry<3>::orderVertices()");
+      carve::TimingBlock block(FUNC_NAME);
+
+      std::vector<vertex_t *> vptr;
+      std::vector<vertex_t *> vmap;
+      std::vector<vertex_t> vout;
+      const size_t N = vertices.size();
+
+      vptr.reserve(N);
+      vout.reserve(N);
+      vmap.resize(N);
+
+      for (size_t i = 0; i != N; ++i) {
+        vptr.push_back(&vertices[i]);
+      }
+      std::sort(vptr.begin(), vptr.end(), VPtrSort<order_t>(order));
+
+      for (size_t i = 0; i != N; ++i) {
+        vout.push_back(*vptr[i]);
+        vmap[vertexToIndex_fast(vptr[i])] = &vout[i];
+      }
+
+      for (size_t i = 0; i < faces.size(); ++i) {
+        face_t &f = faces[i];
+        for (size_t j = 0; j < f.nVertices(); ++j) {
+          f.vertex(j) = vmap[vertexToIndex_fast(f.vertex(j))];
+        }
+      }
+      for (size_t i = 0; i < edges.size(); ++i) {
+        edges[i].v1 = vmap[vertexToIndex_fast(edges[i].v1)];
+        edges[i].v2 = vmap[vertexToIndex_fast(edges[i].v2)];
+      }
+
+      vout.swap(vertices);
+
+      return true;
+    }
+
+
+
+    template<typename T>
+    int Geometry<3>::_faceNeighbourhood(const face_t *f, int depth, T *result) const {
+      if (depth < 0 || f->is_tagged()) return 0;
+
+      f->tag();
+      *(*result)++ = f;
+
+      int r = 1;
+      for (size_t i = 0; i < f->edges.size(); ++i) {
+        const std::vector<const face_t *> &edge_faces = connectivity.edge_to_face[edgeToIndex_fast(f->edges[i])];
+        const face_t *f2 = connectedFace(f, f->edges[i]);
+        if (f2) {
+          r += _faceNeighbourhood(f2, depth - 1, (*result));
+        }
+      }
+      return r;
+    }
+
+
+
+    template<typename T>
+    int Geometry<3>::faceNeighbourhood(const face_t *f, int depth, T result) const {
+      tagable::tag_begin();
+
+      return _faceNeighbourhood(f, depth, &result);
+    }
+
+
+
+    template<typename T>
+    int Geometry<3>::faceNeighbourhood(const edge_t *e, int m_id, int depth, T result) const {
+      tagable::tag_begin();
+
+      int r = 0;
+      const std::vector<const face_t *> &edge_faces = connectivity.edge_to_face[edgeToIndex_fast(e)];
+      for (size_t i = 0; i < edge_faces.size(); ++i) {
+        face_t *f = edge_faces[i];
+        if (f && f->manifold_id == m_id) { r += _faceNeighbourhood(f, depth, &result); }
+      }
+      return r;
+    }
+
+
+
+    template<typename T>
+    int Geometry<3>::faceNeighbourhood(const vertex_t *v, int m_id, int depth, T result) const {
+      tagable::tag_begin();
+
+      int r = 0;
+      const std::vector<const face_t *> &vertex_faces = connectivity.vertex_to_face[vertexToIndex_fast(v)];
+      for (size_t i = 0; i < vertex_faces.size(); ++i) {
+        face_t *f = vertex_faces[i];
+        if (f && f->manifold_id == m_id) { r += _faceNeighbourhood(f, depth, &result); }
+      }
+      return r;
+    }
+
+
+
+    // accessing connectivity information.
+    template<typename T>
+    int Geometry<3>::vertexToEdges(const vertex_t *v, T result) const {
+      std::vector<const edge_t *> &e = connectivity.vertex_to_edge[vertexToIndex_fast(v)];
+      std::copy(e.begin(), e.end(), result);
+      return e.size();
+    }
+
+
+
+    template<typename T>
+    int Geometry<3>::vertexToFaces(const vertex_t *v, T result) const {
+      const std::vector<const face_t *> &vertex_faces = connectivity.vertex_to_face[vertexToIndex_fast(v)];
+      int c = 0;
+      for (size_t i = 0; i < vertex_faces.size(); ++i) {
+        *result++ = vertex_faces[i]; ++c;
+      }
+      return c;
+    }
+
+
+
+    template<typename T>
+    int Geometry<3>::edgeToFaces(const edge_t *e, T result) const {
+      const std::vector<const face_t *> &edge_faces = connectivity.edge_to_face[edgeToIndex_fast(e)];
+      int c = 0;
+      for (size_t i = 0; i < edge_faces.size(); ++i) {
+        if (edge_faces[i] != NULL) { *result++ = edge_faces[i]; ++c; }
+      }
+      return c;
+    }
+
+
+
+    inline const Geometry<3>::face_t *Geometry<3>::connectedFace(const face_t *f, const edge_t *e) const {
+      const std::vector<const face_t *> &edge_faces = connectivity.edge_to_face[edgeToIndex_fast(e)];
+      for (size_t i = 0; i < (edge_faces.size() & ~1U); i++) {
+        if (edge_faces[i] == f) return edge_faces[i^1];
+      }
+      return NULL;
+    }
+
+
+
+    inline void Polyhedron::invert(int m_id) {
+      std::vector<bool> selected_manifolds(manifold_is_closed.size(), false);
+      if (m_id >=0 && (unsigned)m_id < selected_manifolds.size()) selected_manifolds[m_id] = true;
+      invert(selected_manifolds);
+    }
+
+
+    
+    inline void Polyhedron::invert() {
+      invertAll();
+    }
+
+
+
+    inline bool Polyhedron::edgeOnManifold(const edge_t *e, int m_id) const {
+      const std::vector<const face_t *> &edge_faces = connectivity.edge_to_face[edgeToIndex_fast(e)];
+
+      for (size_t i = 0; i < edge_faces.size(); ++i) {
+        if (edge_faces[i] && edge_faces[i]->manifold_id == m_id) return true;
+      }
+      return false;
+    }
+
+    inline bool Polyhedron::vertexOnManifold(const vertex_t *v, int m_id) const {
+      const std::vector<const face_t *> &f = connectivity.vertex_to_face[vertexToIndex_fast(v)];
+
+      for (size_t i = 0; i < f.size(); ++i) {
+        if (f[i]->manifold_id == m_id) return true;
+      }
+      return false;
+    }
+
+
+
+    template<typename T>
+    int Polyhedron::edgeManifolds(const edge_t *e, T result) const {
+      const std::vector<const face_t *> &edge_faces = connectivity.edge_to_face[edgeToIndex_fast(e)];
+
+      for (size_t i = 0; i < (edge_faces.size() & ~1U); i += 2) {
+        const face_t *f1 = edge_faces[i];
+        const face_t *f2 = edge_faces[i+1];
+        assert (f1 || f2);
+        if (f1)
+          *result++ = f1->manifold_id;
+        else if (f2)
+          *result++ = f2->manifold_id;
+      }
+      return edge_faces.size() >> 1;
+    }
+
+
+
+    template<typename T>
+    int Polyhedron::vertexManifolds(const vertex_t *v, T result) const {
+      const std::vector<const face_t *> &f = connectivity.vertex_to_face[vertexToIndex_fast(v)];
+      std::set<int> em;
+
+      for (size_t i = 0; i < f.size(); ++i) {
+        em.insert(f[i]->manifold_id);
+      }
+
+      std::copy(em.begin(), em.end(), result);
+      return em.size();
+    }
+
+
+
+    template<typename T>
+    void Polyhedron::transform(const T &xform) {
+      for (size_t i = 0; i < vertices.size(); i++) {
+        vertices[i].v = xform(vertices[i].v);
+      }
+      faceRecalc();
+      init();
+    }
+
+
+
+    inline size_t Polyhedron::manifoldCount() const {
+      return manifold_is_closed.size();
+    }
+
+
+
+    inline bool Polyhedron::hasOpenManifolds() const {
+      for (size_t i = 0; i < manifold_is_closed.size(); ++i) {
+        if (!manifold_is_closed[i]) return true;
+      }
+      return false;
+    }
+
+
+
+    inline std::ostream &operator<<(std::ostream &o, const Polyhedron &p) {
+      p.print(o);
+      return o;
+    }
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/polyline.hpp b/extern/carve/include/carve/polyline.hpp
new file mode 100644
index 00000000000..a6789f8d0c5
--- /dev/null
+++ b/extern/carve/include/carve/polyline.hpp
@@ -0,0 +1,24 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/polyline_decl.hpp>
+#include <carve/polyline_impl.hpp>
+#include <carve/polyline_iter.hpp>
diff --git a/extern/carve/include/carve/polyline_decl.hpp b/extern/carve/include/carve/polyline_decl.hpp
new file mode 100644
index 00000000000..a29c56656ff
--- /dev/null
+++ b/extern/carve/include/carve/polyline_decl.hpp
@@ -0,0 +1,151 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#include <iterator>
+#include <list>
+#include <iterator>
+#include <limits>
+
+#include <carve/carve.hpp>
+#include <carve/tag.hpp>
+#include <carve/geom.hpp>
+#include <carve/kd_node.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/aabb.hpp>
+
+namespace carve {
+  namespace line {
+
+    struct PolylineEdge;
+    struct Polyline;
+    struct polyline_vertex_const_iter;
+    struct polyline_vertex_iter;
+    struct polyline_edge_const_iter;
+    struct polyline_edge_iter;
+
+
+
+    struct Vertex : public tagable {
+      carve::geom3d::Vector v;
+      std::list<std::pair<PolylineEdge *, PolylineEdge *> > edge_pairs;
+
+      void addEdgePair(PolylineEdge *in, PolylineEdge *out) {
+        edge_pairs.push_back(std::make_pair(in, out));
+      }
+    };
+
+
+
+    struct vec_adapt_vertex_ptr {
+      const carve::geom3d::Vector &operator()(const Vertex * const &v) { return v->v; }
+      carve::geom3d::Vector &operator()(Vertex *&v) { return v->v; }
+    };
+
+
+
+    struct PolylineEdge : public tagable {
+      Polyline *parent;
+      unsigned edgenum;
+      Vertex *v1, *v2;
+
+      PolylineEdge(Polyline *_parent, int _edgenum, Vertex *_v1, Vertex *_v2);
+
+      carve::geom3d::AABB aabb() const;
+
+      inline PolylineEdge *prevEdge() const;
+      inline PolylineEdge *nextEdge() const;
+    };
+
+
+
+    struct Polyline {
+      bool closed;
+      std::vector<PolylineEdge *> edges;
+
+      Polyline();
+
+      size_t vertexCount() const;
+
+      size_t edgeCount() const;
+
+      const PolylineEdge *edge(size_t e) const;
+
+      PolylineEdge *edge(size_t e);
+
+      const Vertex *vertex(size_t v) const;
+
+      Vertex *vertex(size_t v);
+
+      bool isClosed() const;
+
+      polyline_vertex_const_iter vbegin() const;
+      polyline_vertex_const_iter vend() const;
+      polyline_vertex_iter vbegin();
+      polyline_vertex_iter vend();
+
+      polyline_edge_const_iter ebegin() const;
+      polyline_edge_const_iter eend() const;
+      polyline_edge_iter ebegin();
+      polyline_edge_iter eend();
+
+      carve::geom3d::AABB aabb() const;
+
+      template<typename iter_t>
+      void _init(bool c, iter_t begin, iter_t end, std::vector<Vertex> &vertices);
+
+      template<typename iter_t>
+      void _init(bool closed, iter_t begin, iter_t end, std::vector<Vertex> &vertices, std::forward_iterator_tag);
+
+      template<typename iter_t>
+      void _init(bool closed, iter_t begin, iter_t end, std::vector<Vertex> &vertices, std::random_access_iterator_tag);
+
+      template<typename iter_t>
+      Polyline(bool closed, iter_t begin, iter_t end, std::vector<Vertex> &vertices);
+
+      ~Polyline() {
+        for (size_t i = 0; i < edges.size(); ++i) {
+          delete edges[i];
+        }
+      }
+    };
+
+
+
+    struct PolylineSet {
+      typedef std::list<Polyline *> line_list;
+      typedef line_list::iterator line_iter;
+      typedef line_list::const_iterator const_line_iter;
+
+      std::vector<Vertex> vertices;
+      line_list lines;
+      carve::geom3d::AABB aabb;
+
+      PolylineSet(const std::vector<carve::geom3d::Vector> &points);
+      PolylineSet() {
+      }
+
+      template<typename iter_t>
+      void addPolyline(bool closed, iter_t begin, iter_t end);
+
+      void sortVertices(const carve::geom3d::Vector &axis);
+
+      size_t vertexToIndex_fast(const Vertex *v) const;
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/polyline_impl.hpp b/extern/carve/include/carve/polyline_impl.hpp
new file mode 100644
index 00000000000..3c17980a9af
--- /dev/null
+++ b/extern/carve/include/carve/polyline_impl.hpp
@@ -0,0 +1,160 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+namespace carve {
+  namespace line {
+
+    inline PolylineEdge::PolylineEdge(Polyline *_parent, int _edgenum, Vertex *_v1, Vertex *_v2) :
+        tagable(), parent(_parent), edgenum(_edgenum), v1(_v1), v2(_v2) {
+    }
+
+    inline carve::geom3d::AABB PolylineEdge::aabb() const {
+      carve::geom3d::AABB a;
+      a.fit(v1->v, v2->v);
+      return a;
+    }
+
+    inline PolylineEdge *PolylineEdge::prevEdge() const {
+      if (edgenum) {
+        return parent->edge(edgenum - 1);
+      } else {
+        if (parent->closed) {
+          return parent->edge(parent->edgeCount() - 1);
+        } else {
+          return NULL;
+        }
+      }
+    }
+
+    inline PolylineEdge *PolylineEdge::nextEdge() const {
+      if (edgenum + 1 < parent->edgeCount()) {
+        return parent->edge(edgenum + 1);
+      } else {
+        if (parent->closed) {
+          return parent->edge(0);
+        } else {
+          return NULL;
+        }
+      }
+    }
+
+
+
+    inline Polyline::Polyline() : edges() {
+    }
+
+    inline size_t Polyline::vertexCount() const {
+      return edgeCount() + (closed ? 0 : 1);
+    }
+
+    inline size_t Polyline::edgeCount() const {
+      return edges.size();
+    }
+
+    inline const PolylineEdge *Polyline::edge(size_t e) const {
+      return edges[e % edges.size()];
+    }
+
+    inline PolylineEdge *Polyline::edge(size_t e) {
+      return edges[e % edges.size()];
+    }
+
+    inline const Vertex *Polyline::vertex(size_t v) const {
+      if (closed) {
+        v %= edgeCount();
+      } else if (v >= edgeCount()) {
+        return v == edgeCount() ? edges.back()->v2 : NULL;
+      }
+      return edges[v]->v1;
+    }
+
+    inline Vertex *Polyline::vertex(size_t v) {
+      if (closed) {
+        v %= edgeCount();
+      } else if (v >= edgeCount()) {
+        return v == edgeCount() ? edges.back()->v2 : NULL;
+      }
+      return edges[v]->v1;
+    }
+
+    inline bool Polyline::isClosed() const {
+      return closed;
+    }
+
+    template<typename iter_t>
+    void Polyline::_init(bool c, iter_t begin, iter_t end, std::vector<Vertex> &vertices) {
+      closed = c;
+
+      PolylineEdge *e;
+      if (begin == end) return;
+      size_t v1 = (int)*begin++;
+      if (begin == end) return;
+
+      while (begin != end) {
+        size_t v2 = (int)*begin++;
+        e = new PolylineEdge(this, edges.size(), &vertices[v1], &vertices[v2]);
+        edges.push_back(e);
+        v1 = v2;
+      }
+
+      if (closed) {
+        e = new PolylineEdge(this, edges.size(), edges.back()->v2, edges.front()->v1);
+        edges.push_back(e);
+
+        edges.front()->v1->addEdgePair(edges.back(), edges.front());
+        for (size_t i = 1; i < edges.size(); ++i) {
+          edges[i]->v1->addEdgePair(edges[i-1], edges[i]);
+        }
+      } else {
+        edges.front()->v1->addEdgePair(NULL, edges.front());
+        for (size_t i = 1; i < edges.size(); ++i) {
+          edges[i]->v1->addEdgePair(edges[i-1], edges[i]);
+        }
+        edges.back()->v2->addEdgePair(edges.back(), NULL);
+      }
+    }
+
+    template<typename iter_t>
+    void Polyline::_init(bool closed, iter_t begin, iter_t end, std::vector<Vertex> &vertices, std::forward_iterator_tag) {
+      _init(closed, begin, end, vertices);
+    }
+
+    template<typename iter_t>
+    void Polyline::_init(bool closed, iter_t begin, iter_t end, std::vector<Vertex> &vertices, std::random_access_iterator_tag) {
+      edges.reserve(end - begin - (closed ? 0 : 1));
+      _init(closed, begin, end, vertices);
+    }
+
+    template<typename iter_t>
+    Polyline::Polyline(bool closed, iter_t begin, iter_t end, std::vector<Vertex> &vertices) {
+      _init(closed, begin, end, vertices, typename std::iterator_traits<iter_t>::iterator_category());
+    }
+
+
+
+    template<typename iter_t>
+    void PolylineSet::addPolyline(bool closed, iter_t begin, iter_t end) {
+      Polyline *p = new Polyline(closed, begin, end, vertices);
+      lines.push_back(p);
+    }
+
+    inline size_t PolylineSet::vertexToIndex_fast(const Vertex *v) const {
+      return v - &vertices[0];
+    }
+  }
+}
diff --git a/extern/carve/include/carve/polyline_iter.hpp b/extern/carve/include/carve/polyline_iter.hpp
new file mode 100644
index 00000000000..5092f9abecd
--- /dev/null
+++ b/extern/carve/include/carve/polyline_iter.hpp
@@ -0,0 +1,198 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+#pragma once
+
+#include <iterator>
+#include <list>
+#include <iterator>
+#include <limits>
+
+#include <carve/polyline_decl.hpp>
+
+namespace carve {
+  namespace line {
+
+    struct polyline_vertex_iter : public std::iterator<std::random_access_iterator_tag, Vertex *> {
+      Polyline *base;
+      size_t idx;
+
+      polyline_vertex_iter(Polyline *_base) : base(_base), idx(0) {
+      }
+
+      polyline_vertex_iter(Polyline *_base, size_t _idx) : base(_base), idx(_idx) {
+      }
+
+      polyline_vertex_iter operator++(int) { return polyline_vertex_iter(base, idx++); }
+      polyline_vertex_iter &operator++() { ++idx; return *this; }
+      polyline_vertex_iter &operator+=(int v) { idx += v; return *this; }
+
+      polyline_vertex_iter operator--(int) { return polyline_vertex_iter(base, idx--); }
+      polyline_vertex_iter &operator--() { --idx; return *this; }
+      polyline_vertex_iter &operator-=(int v) { idx -= v; return *this; }
+
+      Vertex *operator*() const {
+        return base->vertex(idx);
+      }
+    };
+
+
+
+    static inline ptrdiff_t operator-(const polyline_vertex_iter &a, const polyline_vertex_iter &b) { return a.idx - b.idx; }
+                
+    static inline bool operator==(const polyline_vertex_iter&a, const polyline_vertex_iter &b) { return a.idx == b.idx; }
+    static inline bool operator!=(const polyline_vertex_iter&a, const polyline_vertex_iter &b) { return a.idx != b.idx; }
+    static inline bool operator<(const polyline_vertex_iter&a, const polyline_vertex_iter &b) { return a.idx < b.idx; }
+    static inline bool operator>(const polyline_vertex_iter&a, const polyline_vertex_iter &b) { return a.idx > b.idx; }
+    static inline bool operator<=(const polyline_vertex_iter&a, const polyline_vertex_iter &b) { return a.idx <= b.idx; }
+    static inline bool operator>=(const polyline_vertex_iter&a, const polyline_vertex_iter &b) { return a.idx >= b.idx; }
+
+
+
+    struct polyline_vertex_const_iter : public std::iterator<std::random_access_iterator_tag, Vertex *> {
+      const Polyline *base;
+      size_t idx;
+
+      polyline_vertex_const_iter(const Polyline *_base) : base(_base), idx(0) {
+      }
+
+      polyline_vertex_const_iter(const Polyline *_base, size_t _idx) : base(_base), idx(_idx) {
+      }
+
+      polyline_vertex_const_iter operator++(int) { return polyline_vertex_const_iter(base, idx++); }
+      polyline_vertex_const_iter &operator++() { ++idx; return *this; }
+      polyline_vertex_const_iter &operator+=(int v) { idx += v; return *this; }
+
+      polyline_vertex_const_iter operator--(int) { return polyline_vertex_const_iter(base, idx--); }
+      polyline_vertex_const_iter &operator--() { --idx; return *this; }
+      polyline_vertex_const_iter &operator-=(int v) { idx -= v; return *this; }
+
+      const Vertex *operator*() const {
+        return base->vertex(idx);
+      }
+    };
+
+
+
+    static inline ptrdiff_t operator-(const polyline_vertex_const_iter &a, const polyline_vertex_const_iter &b) { return a.idx - b.idx; }
+                
+    static inline bool operator==(const polyline_vertex_const_iter&a, const polyline_vertex_const_iter &b) { return a.idx == b.idx; }
+    static inline bool operator!=(const polyline_vertex_const_iter&a, const polyline_vertex_const_iter &b) { return a.idx != b.idx; }
+    static inline bool operator<(const polyline_vertex_const_iter&a, const polyline_vertex_const_iter &b) { return a.idx < b.idx; }
+    static inline bool operator>(const polyline_vertex_const_iter&a, const polyline_vertex_const_iter &b) { return a.idx > b.idx; }
+    static inline bool operator<=(const polyline_vertex_const_iter&a, const polyline_vertex_const_iter &b) { return a.idx <= b.idx; }
+    static inline bool operator>=(const polyline_vertex_const_iter&a, const polyline_vertex_const_iter &b) { return a.idx >= b.idx; }
+
+    inline polyline_vertex_const_iter Polyline::vbegin() const { 
+      return polyline_vertex_const_iter(this, 0);
+    }
+    inline polyline_vertex_const_iter Polyline::vend() const { 
+      return polyline_vertex_const_iter(this, vertexCount());
+    }
+    inline polyline_vertex_iter Polyline::vbegin() { 
+      return polyline_vertex_iter(this, 0);
+    }
+    inline polyline_vertex_iter Polyline::vend() { 
+      return polyline_vertex_iter(this, vertexCount());
+    }
+
+
+
+    struct polyline_edge_iter : public std::iterator<std::random_access_iterator_tag, PolylineEdge *> {
+      Polyline *base;
+      size_t idx;
+
+      polyline_edge_iter(Polyline *_base) : base(_base), idx(0) {
+      }
+
+      polyline_edge_iter(Polyline *_base, size_t _idx) : base(_base), idx(_idx) {
+      }
+
+      polyline_edge_iter operator++(int) { return polyline_edge_iter(base, idx++); }
+      polyline_edge_iter &operator++() { ++idx; return *this; }
+      polyline_edge_iter &operator+=(int v) { idx += v; return *this; }
+
+      polyline_edge_iter operator--(int) { return polyline_edge_iter(base, idx--); }
+      polyline_edge_iter &operator--() { --idx; return *this; }
+      polyline_edge_iter &operator-=(int v) { idx -= v; return *this; }
+
+      PolylineEdge *operator*() const {
+        return base->edge(idx);
+      }
+    };
+
+
+
+    static inline int operator-(const polyline_edge_iter&a, const polyline_edge_iter &b) { return a.idx - b.idx; }
+                
+    static inline bool operator==(const polyline_edge_iter&a, const polyline_edge_iter &b) { return a.idx == b.idx; }
+    static inline bool operator!=(const polyline_edge_iter&a, const polyline_edge_iter &b) { return a.idx != b.idx; }
+    static inline bool operator<(const polyline_edge_iter&a, const polyline_edge_iter &b) { return a.idx < b.idx; }
+    static inline bool operator>(const polyline_edge_iter&a, const polyline_edge_iter &b) { return a.idx > b.idx; }
+    static inline bool operator<=(const polyline_edge_iter&a, const polyline_edge_iter &b) { return a.idx <= b.idx; }
+    static inline bool operator>=(const polyline_edge_iter&a, const polyline_edge_iter &b) { return a.idx >= b.idx; }
+
+
+
+    struct polyline_edge_const_iter : public std::iterator<std::random_access_iterator_tag, PolylineEdge *> {
+      const Polyline *base;
+      size_t idx;
+
+      polyline_edge_const_iter(const Polyline *_base) : base(_base), idx(0) {
+      }
+
+      polyline_edge_const_iter(const Polyline *_base, size_t _idx) : base(_base), idx(_idx) {
+      }
+
+      polyline_edge_const_iter operator++(int) { return polyline_edge_const_iter(base, idx++); }
+      polyline_edge_const_iter &operator++() { ++idx; return *this; }
+      polyline_edge_const_iter &operator+=(int v) { idx += v; return *this; }
+
+      polyline_edge_const_iter operator--(int) { return polyline_edge_const_iter(base, idx--); }
+      polyline_edge_const_iter &operator--() { --idx; return *this; }
+      polyline_edge_const_iter &operator-=(int v) { idx -= v; return *this; }
+
+      const PolylineEdge *operator*() const {
+        return base->edge(idx);
+      }
+    };
+
+
+
+    static inline int operator-(const polyline_edge_const_iter&a, const polyline_edge_const_iter &b) { return a.idx - b.idx; }
+                
+    static inline bool operator==(const polyline_edge_const_iter&a, const polyline_edge_const_iter &b) { return a.idx == b.idx; }
+    static inline bool operator!=(const polyline_edge_const_iter&a, const polyline_edge_const_iter &b) { return a.idx != b.idx; }
+    static inline bool operator<(const polyline_edge_const_iter&a, const polyline_edge_const_iter &b) { return a.idx < b.idx; }
+    static inline bool operator>(const polyline_edge_const_iter&a, const polyline_edge_const_iter &b) { return a.idx > b.idx; }
+    static inline bool operator<=(const polyline_edge_const_iter&a, const polyline_edge_const_iter &b) { return a.idx <= b.idx; }
+    static inline bool operator>=(const polyline_edge_const_iter&a, const polyline_edge_const_iter &b) { return a.idx >= b.idx; }
+
+    inline polyline_edge_const_iter Polyline::ebegin() const { 
+      return polyline_edge_const_iter(this, 0);
+    }
+    inline polyline_edge_const_iter Polyline::eend() const { 
+      return polyline_edge_const_iter(this, edgeCount());
+    }
+    inline polyline_edge_iter Polyline::ebegin() { 
+      return polyline_edge_iter(this, 0);
+    }
+    inline polyline_edge_iter Polyline::eend() { 
+      return polyline_edge_iter(this, edgeCount());
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/rescale.hpp b/extern/carve/include/carve/rescale.hpp
new file mode 100644
index 00000000000..6478298cfe6
--- /dev/null
+++ b/extern/carve/include/carve/rescale.hpp
@@ -0,0 +1,100 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/vector.hpp>
+#include <carve/aabb.hpp>
+#include <carve/matrix.hpp>
+
+#include <limits>
+
+namespace carve {
+  namespace rescale {
+
+    template<typename T>
+    T calc_scale(T max) {
+      const int radix = std::numeric_limits<T>::radix;
+
+      T div = T(1);
+      T m = fabs(max);
+      while (div < m) div *= radix;
+      m *= radix;
+      while (div > m) div /= radix;
+      return div;
+    }
+
+    template<typename T>
+    T calc_delta(T min, T max) {
+      const int radix = std::numeric_limits<T>::radix;
+
+      if (min >= T(0) || max <= T(0)) {
+        bool neg = false;
+        if (max <= T(0)) {
+          min = -min;
+          max = -max;
+          std::swap(min, max);
+          neg = true;
+        }
+        T t = T(1);
+        while (t > max) t /= radix;
+        while (t <= max/radix) t *= radix;
+        volatile T temp = t + min;
+        temp -= t;
+        if (neg) temp = -temp;
+        return temp;
+      } else {
+        return T(0);
+      }
+    }
+
+    struct rescale {
+      double dx, dy, dz, scale;
+
+      void init(double minx, double miny, double minz, double maxx, double maxy, double maxz) {
+        dx = calc_delta(minx, maxx); minx -= dx; maxx -= dx;
+        dy = calc_delta(miny, maxy); miny -= dy; maxy -= dy;
+        dz = calc_delta(minz, maxz); minz -= dz; maxz -= dz;
+        scale = calc_scale(std::max(std::max(fabs(minz), fabs(maxz)),
+                                    std::max(std::max(fabs(minx), fabs(maxx)),
+                                             std::max(fabs(miny), fabs(maxy)))));
+      }
+
+      rescale(double minx, double miny, double minz, double maxx, double maxy, double maxz) {
+        init(minx, miny, minz, maxx, maxy, maxz);
+      }
+      rescale(const carve::geom3d::Vector &min, const carve::geom3d::Vector &max) {
+        init(min.x, min.y, min.z, max.x, max.y, max.z);
+      }
+    };
+
+    struct fwd {
+      rescale r;
+      fwd(const rescale &_r) : r(_r) { }
+      carve::geom3d::Vector operator()(const carve::geom3d::Vector &v) const { return carve::geom::VECTOR((v.x - r.dx) / r.scale, (v.y - r.dy) / r.scale, (v.z - r.dz) / r.scale); }
+    };
+
+    struct rev {
+      rescale r;
+      rev(const rescale &_r) : r(_r) { }
+      carve::geom3d::Vector operator()(const carve::geom3d::Vector &v) const { return carve::geom::VECTOR((v.x * r.scale) + r.dx, (v.y * r.scale) + r.dy, (v.z * r.scale) + r.dz); }
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/rtree.hpp b/extern/carve/include/carve/rtree.hpp
new file mode 100644
index 00000000000..77f93c14e08
--- /dev/null
+++ b/extern/carve/include/carve/rtree.hpp
@@ -0,0 +1,501 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom.hpp>
+#include <carve/aabb.hpp>
+
+#include <iostream>
+
+#include <cmath>
+#include <limits>
+
+#if defined(HAVE_STDINT_H)
+# include <stdint.h>
+#endif
+
+namespace carve {
+  namespace geom {
+
+    template<unsigned ndim,
+             typename data_t,
+             typename aabb_calc_t = carve::geom::get_aabb<ndim, data_t> >
+    struct RTreeNode {
+      typedef aabb<ndim> aabb_t;
+      typedef vector<ndim> vector_t;
+      typedef RTreeNode<ndim, data_t, aabb_calc_t> node_t;
+
+      aabb_t bbox;
+      node_t *child;
+      node_t *sibling;
+      std::vector<data_t> data;
+
+      aabb_t getAABB() const { return bbox; }
+
+
+
+      struct data_aabb_t {
+        aabb_t bbox;
+        data_t data;
+
+        data_aabb_t() { }
+        data_aabb_t(const data_t &_data) : bbox(aabb_calc_t()(_data)), data(_data) {
+        }
+
+        aabb_t getAABB() const { return bbox; }
+
+        struct cmp {
+          size_t dim;
+          cmp(size_t _dim) : dim(_dim) { }
+          bool operator()(const data_aabb_t &a, const data_aabb_t &b) {
+            return a.bbox.pos.v[dim] < b.bbox.pos.v[dim];
+          }
+        };
+      };
+
+      // Fill an rtree node with a set of (data, aabb) pairs.
+      template<typename iter_t>
+      void _fill(iter_t begin, iter_t end, data_aabb_t) {
+        data.reserve(std::distance(begin, end));
+        for (iter_t i = begin; i != end; ++i) {
+          data.push_back((*i).data);
+        }
+        bbox.fit(begin, end);
+      }
+
+      // Fill an rtree node with a set of data.
+      template<typename iter_t>
+      void _fill(iter_t begin, iter_t end, data_t) {
+        data.reserve(std::distance(begin, end));
+        std::copy(begin, end, std::back_inserter(data));
+        bbox.fit(begin, end, aabb_calc_t());
+      }
+
+      // Fill an rtree node with a set of child nodes.
+      template<typename iter_t>
+      void _fill(iter_t begin, iter_t end, node_t *) {
+        iter_t i = begin;
+        node_t *curr = child = *i;
+        while (++i != end) {
+          curr->sibling = *i;
+          curr = curr->sibling;
+        }
+        bbox.fit(begin, end);
+      }
+
+      // Search the rtree for objects that intersect obj (generally an aabb).
+      // The aabb class must provide a method intersects(obj_t).
+      template<typename obj_t, typename out_iter_t>
+      void search(const obj_t &obj, out_iter_t out) const {
+        if (!bbox.intersects(obj)) return;
+        if (child) {
+          for (node_t *node = child; node; node = node->sibling) {
+            node->search(obj, out);
+          }
+        } else {
+          std::copy(data.begin(), data.end(), out);
+        }
+      }
+
+      // update the bounding box extents of nodes that intersect obj (generally an aabb).
+      // The aabb class must provide a method intersects(obj_t).
+      template<typename obj_t>
+      void updateExtents(const obj_t &obj) {
+        if (!bbox.intersects(obj)) return;
+
+        if (child) {
+          node_t *node = child;
+          node->updateExtents(obj);
+          bbox = node->bbox;
+          for (node = node->sibling; node; node = node->sibling) {
+            node->updateExtents(obj);
+            bbox.unionAABB(node->bbox);
+          }
+        } else {
+          bbox.fit(data.begin(), data.end());
+        }
+      }
+
+      // update the bounding box extents of nodes that intersect obj (generally an aabb).
+      // The aabb class must provide a method intersects(obj_t).
+      bool remove(const data_t &val, const aabb_t &val_aabb) {
+        if (!bbox.intersects(val_aabb)) return false;
+
+        if (child) {
+          node_t *node = child;
+          node->remove(val, val_aabb);
+          bbox = node->bbox;
+          bool removed = false;
+          for (node = node->sibling; node; node = node->sibling) {
+            if (!removed) removed = node->remove(val, val_aabb);
+            bbox.unionAABB(node->bbox);
+          }
+          return removed;
+        } else {
+          typename std::vector<data_t>::iterator i = std::remove(data.begin(), data.end(), val);
+          if (i == data.end()) {
+            return false;
+          }
+          data.erase(i, data.end());
+          bbox.fit(data.begin(), data.end());
+          return true;
+        }
+      }
+
+      template<typename iter_t>
+      RTreeNode(iter_t begin, iter_t end) : bbox(), child(NULL), sibling(NULL), data() {
+        _fill(begin, end, typename std::iterator_traits<iter_t>::value_type());
+      }
+
+
+
+      // functor for ordering nodes by increasing aabb midpoint, along a specified axis.
+      struct aabb_cmp_mid {
+        size_t dim;
+        aabb_cmp_mid(size_t _dim) : dim(_dim) { }
+
+        bool operator()(const node_t *a, const node_t *b) {
+          return a->bbox.mid(dim) < b->bbox.mid(dim);
+        }
+        bool operator()(const data_aabb_t &a, const data_aabb_t &b) {
+          return a.bbox.mid(dim) < b.bbox.mid(dim);
+        }
+      };
+
+      // functor for ordering nodes by increasing aabb minimum, along a specified axis.
+      struct aabb_cmp_min {
+        size_t dim;
+        aabb_cmp_min(size_t _dim) : dim(_dim) { }
+
+        bool operator()(const node_t *a, const node_t *b) {
+          return a->bbox.min(dim) < b->bbox.min(dim);
+        }
+        bool operator()(const data_aabb_t &a, const data_aabb_t &b) {
+          return a.bbox.min(dim) < b.bbox.min(dim);
+        }
+      };
+
+      // functor for ordering nodes by increasing aabb maximum, along a specified axis.
+      struct aabb_cmp_max {
+        size_t dim;
+        aabb_cmp_max(size_t _dim) : dim(_dim) { }
+
+        bool operator()(const node_t *a, const node_t *b) {
+          return a->bbox.max(dim) < b->bbox.max(dim);
+        }
+        bool operator()(const data_aabb_t &a, const data_aabb_t &b) {
+          return a.bbox.max(dim) < b.bbox.max(dim);
+        }
+      };
+
+      // facade for projecting node bounding box onto an axis.
+      struct aabb_extent {
+        size_t dim;
+        aabb_extent(size_t _dim) : dim(_dim) { }
+
+        double min(const node_t *a) { return a->bbox.pos.v[dim] - a->bbox.extent.v[dim]; }
+        double max(const node_t *a) { return a->bbox.pos.v[dim] + a->bbox.extent.v[dim]; }
+        double len(const node_t *a) { return 2.0 * a->bbox.extent.v[dim]; }
+        double min(const data_aabb_t &a) { return a.bbox.pos.v[dim] - a.bbox.extent.v[dim]; }
+        double max(const data_aabb_t &a) { return a.bbox.pos.v[dim] + a.bbox.extent.v[dim]; }
+        double len(const data_aabb_t &a) { return 2.0 * a.bbox.extent.v[dim]; }
+      };
+
+      template<typename iter_t>
+      static void makeNodes(const iter_t begin,
+                            const iter_t end,
+                            size_t dim_num,
+                            uint32_t dim_mask,
+                            size_t child_size,
+                            std::vector<node_t *> &out) {
+        const size_t N = std::distance(begin, end);
+
+        size_t dim = ndim;
+        double r_best = N+1;
+
+        // find the sparsest remaining dimension to partition by.
+        for (size_t i = 0; i < ndim; ++i) {
+          if (dim_mask & (1U << i)) continue;
+          aabb_extent extent(i);
+          double dmin, dmax, dsum;
+
+          dmin = extent.min(*begin);
+          dmax = extent.max(*begin);
+          dsum = 0.0;
+          for (iter_t j = begin; j != end; ++j) {
+            dmin = std::min(dmin, extent.min(*j));
+            dmax = std::max(dmax, extent.max(*j));
+            dsum += extent.len(*j);
+          }
+          double r = dsum ? dsum / (dmax - dmin) : 0.0;
+          if (r_best > r) {
+            dim = i;
+            r_best = r;
+          }
+        }
+
+        CARVE_ASSERT(dim < ndim);
+
+        // dim = dim_num;
+
+        const size_t P = (N + child_size - 1) / child_size;
+        const size_t n_parts = (size_t)std::ceil(std::pow((double)P, 1.0 / (ndim - dim_num)));
+
+        std::sort(begin, end, aabb_cmp_mid(dim));
+
+        if (dim_num == ndim - 1 || n_parts == 1) {
+          for (size_t i = 0, s = 0, e = 0; i < P; ++i, s = e) {
+            e = N * (i+1) / P;
+            CARVE_ASSERT(e - s <= child_size);
+            out.push_back(new node_t(begin + s, begin + e));
+          }
+        } else {
+          for (size_t i = 0, s = 0, e = 0; i < n_parts; ++i, s = e) {
+            e = N * (i+1) / n_parts;
+            makeNodes(begin + s, begin + e, dim_num + 1, dim_mask | (1U << dim), child_size, out);
+          }
+        }
+      }
+
+      static node_t *construct_STR(std::vector<data_aabb_t> &data, size_t leaf_size, size_t internal_size) {
+        std::vector<node_t *> out;
+        makeNodes(data.begin(), data.end(), 0, 0, leaf_size, out);
+
+        while (out.size() > 1) {
+          std::vector<node_t *> next;
+          makeNodes(out.begin(), out.end(), 0, 0, internal_size, next);
+          std::swap(out, next);
+        }
+
+        CARVE_ASSERT(out.size() == 1);
+        return out[0];
+      }
+
+      template<typename iter_t>
+      static node_t *construct_STR(const iter_t &begin,
+                                   const iter_t &end,
+                                   size_t leaf_size,
+                                   size_t internal_size) {
+        std::vector<data_aabb_t> data;
+        data.reserve(std::distance(begin, end));
+        for (iter_t i = begin; i != end; ++i) {
+          data.push_back(*i);
+        }
+        return construct_STR(data, leaf_size, internal_size);
+      }
+
+
+      template<typename iter_t>
+      static node_t *construct_STR(const iter_t &begin1,
+                                   const iter_t &end1,
+                                   const iter_t &begin2,
+                                   const iter_t &end2,
+                                   size_t leaf_size,
+                                   size_t internal_size) {
+        std::vector<data_aabb_t> data;
+        data.reserve(std::distance(begin1, end1) + std::distance(begin2, end2));
+        for (iter_t i = begin1; i != end1; ++i) {
+          data.push_back(*i);
+        }
+        for (iter_t i = begin2; i != end2; ++i) {
+          data.push_back(*i);
+        }
+        return construct_STR(data, leaf_size, internal_size);
+      }
+
+
+      struct partition_info {
+        double score;
+        size_t partition_pos;
+
+        partition_info() : score(std::numeric_limits<double>::max()), partition_pos(0) {
+        }
+        partition_info(double _score, size_t _partition_pos) :
+          score(_score),
+          partition_pos(_partition_pos) {
+        }
+      };
+
+      static partition_info findPartition(typename std::vector<data_aabb_t>::iterator base,
+                                          std::vector<size_t>::iterator begin,
+                                          std::vector<size_t>::iterator end,
+                                          size_t part_size) {
+        partition_info best(std::numeric_limits<double>::max(), 0);
+        const size_t N = std::distance(begin, end);
+
+        std::vector<double> rhs_vol(N, 0.0);
+
+        aabb_t rhs = base[begin[N-1]].aabb;
+        rhs_vol[N-1] = rhs.volume();
+        for (size_t i = N - 1; i > 0; ) {
+          rhs.unionAABB(base[begin[--i]].aabb);
+          rhs_vol[i] = rhs.volume();
+        }
+
+        aabb_t lhs = base[begin[0]].aabb;
+        for (size_t i = 1; i < N; ++i) {
+          lhs.unionAABB(base[begin[i]].aabb);
+          if (i % part_size == 0 || (N - i) % part_size == 0) {
+            partition_info curr(lhs.volume() + rhs_vol[i], i);
+            if (best.score > curr.score) best = curr;
+          }
+        }
+        return best;
+      }
+
+      static void partition(typename std::vector<data_aabb_t>::iterator base,
+                            std::vector<size_t>::iterator begin,
+                            std::vector<size_t>::iterator end,
+                            size_t part_size,
+                            std::vector<size_t> &part_num,
+                            size_t &part_next) {
+        const size_t N = std::distance(begin, end);
+
+        partition_info best;
+        partition_info curr;
+        size_t part_curr = part_num[*begin];
+
+        std::vector<size_t> tmp(begin, end);
+
+        for (size_t dim = 0; dim < ndim; ++dim) {
+          std::sort(tmp.begin(), tmp.end(), make_index_sort(base, aabb_cmp_min(dim)));
+          curr = findPartition(base, tmp.begin(), tmp.end(), part_size);
+          if (best.score > curr.score) {
+            best = curr;
+            std::copy(tmp.begin(), tmp.end(), begin);
+          }
+
+          std::sort(tmp.begin(), tmp.end(), make_index_sort(base, aabb_cmp_mid(dim)));
+          curr = findPartition(base, tmp.begin(), tmp.end(), part_size);
+          if (best.score > curr.score) {
+            best = curr;
+            std::copy(tmp.begin(), tmp.end(), begin);
+          }
+
+          std::sort(tmp.begin(), tmp.end(), make_index_sort(base, aabb_cmp_max(dim)));
+          curr = findPartition(base, tmp.begin(), tmp.end(), part_size);
+          if (best.score > curr.score) {
+            best = curr;
+            std::copy(tmp.begin(), tmp.end(), begin);
+          }
+        }
+
+        for (size_t j = 0; j < best.partition_pos; ++j) part_num[begin[j]] = part_curr;
+        for (size_t j = best.partition_pos; j < N; ++j) part_num[begin[j]] = part_next;
+        ++part_next;
+
+        if (best.partition_pos > part_size) {
+          partition(base, begin, begin + best.partition_pos, part_size, part_num, part_next);
+        }
+        if (N - best.partition_pos > part_size) {
+          partition(base, begin + best.partition_pos, end, part_size, part_num, part_next);
+        }
+      }
+
+      static size_t makePartitions(typename std::vector<data_aabb_t>::iterator begin,
+                                   typename std::vector<data_aabb_t>::iterator end,
+                                   size_t part_size,
+                                   std::vector<size_t> &part_num) {
+        const size_t N = std::distance(begin, end);
+        std::vector<size_t> idx;
+        idx.reserve(N);
+        for (size_t i = 0; i < N; ++i) { idx.push_back(i); }
+        size_t part_next = 1;
+
+        partition(begin, idx.begin(), idx.end(), part_size, part_num, part_next);
+        return part_next;
+      }
+
+      static node_t *construct_TGS(typename std::vector<data_aabb_t>::iterator begin,
+                                   typename std::vector<data_aabb_t>::iterator end,
+                                   size_t leaf_size,
+                                   size_t internal_size) {
+        size_t N = std::distance(begin, end);
+
+        if (N <= leaf_size) {
+          return new node_t(begin, end);
+        } else {
+          size_t P = (N + internal_size - 1) / internal_size;
+          std::vector<size_t> part_num(N, 0);
+          P = makePartitions(begin, end, P, part_num);
+
+          size_t S = 0, E = 0;
+          std::vector<node_t *> children;
+          for (size_t i = 0; i < P; ++i) {
+            size_t j = S, k = N;
+            while (true) {
+              while (true) {
+                if (j == k) goto done;
+                else if (part_num[j] == i) ++j;
+                else break;
+              }
+              --k;
+              while (true) {
+                if (j == k) goto done;
+                else if (part_num[k] != i) --k;
+                else break;
+              }
+              std::swap(*(begin+j), *(begin+k));
+              std::swap(part_num[j], part_num[k]);
+              ++j;
+            }
+          done:
+            E = j;
+            children.push_back(construct_TGS(begin + S, begin + E, leaf_size, internal_size));
+            S = E;
+          }
+          return new node_t(children.begin(), children.end());
+        }
+      }
+
+      template<typename iter_t>
+      static node_t *construct_TGS(const iter_t &begin,
+                                   const iter_t &end,
+                                   size_t leaf_size,
+                                   size_t internal_size) {
+        std::vector<data_aabb_t> data;
+        data.reserve(std::distance(begin, end));
+        for (iter_t i = begin; i != end; ++i) {
+          data.push_back(*i);
+        }
+        return construct_TGS(data.begin(), data.end(), leaf_size, internal_size);
+      }
+
+      template<typename iter_t>
+      static node_t *construct_TGS(const iter_t &begin1,
+                                   const iter_t &end1,
+                                   const iter_t &begin2,
+                                   const iter_t &end2,
+                                   size_t leaf_size,
+                                   size_t internal_size) {
+        std::vector<data_aabb_t> data;
+        data.reserve(std::distance(begin1, end1) + std::distance(begin2, end2));
+        for (iter_t i = begin1; i != end1; ++i) {
+          data.push_back(*i);
+        }
+        for (iter_t i = begin2; i != end2; ++i) {
+          data.push_back(*i);
+        }
+        return construct_TGS(data.begin(), data.end(), leaf_size, internal_size);
+      }
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/spacetree.hpp b/extern/carve/include/carve/spacetree.hpp
new file mode 100644
index 00000000000..f2ea2bb83a7
--- /dev/null
+++ b/extern/carve/include/carve/spacetree.hpp
@@ -0,0 +1,264 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom.hpp>
+#include <carve/aabb.hpp>
+#include <carve/vertex_decl.hpp>
+#include <carve/edge_decl.hpp>
+#include <carve/face_decl.hpp>
+
+namespace carve {
+
+  namespace space {
+
+    static inline bool intersection_test(const carve::geom::aabb<3> &aabb, const carve::poly::Face<3> *face) {
+      if (face->nVertices() == 3) {
+        return aabb.intersects(carve::geom::tri<3>(face->vertex(0)->v, face->vertex(1)->v, face->vertex(2)->v));
+      } else {
+        // partial, conservative SAT.
+        return aabb.intersects(face->aabb) && aabb.intersects(face->plane_eqn);
+      }
+    }
+
+    static inline bool intersection_test(const carve::geom::aabb<3> &aabb, const carve::poly::Edge<3> *edge) {
+      return aabb.intersectsLineSegment(edge->v1->v, edge->v2->v);
+    }
+
+    static inline bool intersection_test(const carve::geom::aabb<3> &aabb, const carve::poly::Vertex<3> *vertex) {
+      return aabb.intersects(vertex->v);
+    }
+
+
+
+    struct nodedata_FaceEdge {
+      std::vector<const carve::poly::Face<3> *> faces;
+      std::vector<const carve::poly::Edge<3> *> edges;
+
+      void add(const carve::poly::Face<3> *face) {
+        faces.push_back(face);
+      }
+
+      void add(const carve::poly::Edge<3> *edge) {
+        edges.push_back(edge);
+      }
+
+      template<typename iter_t>
+      void _fetch(iter_t &iter, const carve::poly::Edge<3> *) {
+        std::copy(edges.begin(), edges.end(), iter);
+      }
+
+      template<typename iter_t>
+      void _fetch(iter_t &iter, const carve::poly::Face<3> *) {
+        std::copy(faces.begin(), faces.end(), iter);
+      }
+
+      template<typename node_t>
+      void propagate(node_t *node) {
+      }
+
+      template<typename iter_t>
+      void fetch(iter_t &iter) {
+        return _fetch(iter, std::iterator_traits<iter_t>::value_type);
+      }
+    };
+
+
+
+    const static double SLACK_FACTOR = 1.0009765625;
+    const static unsigned MAX_SPLIT_DEPTH = 32;
+
+
+
+    template<unsigned n_dim, typename nodedata_t>
+    class SpatialSubdivTree {
+
+      typedef carve::geom::aabb<n_dim> aabb_t;
+      typedef carve::geom::vector<n_dim> vector_t;
+
+    public:
+
+      class Node {
+        enum {
+          n_children = 1 << n_dim
+        };
+
+      public:
+        Node *parent;
+        Node *children;
+
+        vector_t min;
+        vector_t max;
+
+        aabb_t aabb;
+
+        nodedata_t data;
+
+      private:
+        Node(const Node &node); // undefined.
+        Node &operator=(const Node &node); // undefined.
+
+        Node() {
+        }
+
+        inline aabb_t makeAABB() const {
+          vector_t centre = 0.5 * (min + max);
+          vector_t size = SLACK_FACTOR * 0.5 * (max - min);
+          return aabb_t(centre, size);
+        }
+
+        void setup(Node *_parent, const vector_t &_min, const vector_t &_max) {
+          parent = _parent;
+          min = _min;
+          max = _max;
+          aabb = makeAABB();
+        }
+
+        void alloc_children() {
+          vector_t mid = 0.5 * (min + max);
+          children = new Node[n_children];
+          for (size_t i = 0; i < (n_children); ++i) {
+            vector_t new_min, new_max;
+            for (size_t c = 0; c < n_dim; ++c) {
+              if (i & (1 << c)) {
+                new_min.v[c] = min.v[c];
+                new_max.v[c] = mid.v[c];
+              } else {
+                new_min.v[c] = mid.v[c];
+                new_max.v[c] = max.v[c];
+              }
+            }
+            children[i].setup(this, new_min, new_max);
+          }
+        }
+
+        void dealloc_children() {
+          delete [] children;
+        }
+
+      public:
+
+        inline bool isLeaf() const { return children == NULL; }
+
+        Node(Node *_parent, const vector_t &_min, const vector_t &_max) : parent(_parent), children(NULL), min(_min), max(_max) {
+          aabb = makeAABB();
+        }
+
+        ~Node() {
+          dealloc_children();
+        }
+
+        bool split() {
+          if (isLeaf()) {
+            alloc_children();
+            data.propagate(this);
+          }
+          return isLeaf();
+        }
+
+        template<typename obj_t>
+        void insert(const obj_t &object) {
+          if (!isLeaf()) {
+            for (size_t i = 0; i < n_children; ++i) {
+              if (intersection_test(children[i].aabb, object)) {
+                children[i].insert(object);
+              }
+            }
+          } else {
+            data.add(object);
+          }
+        }
+
+        template<typename obj_t>
+        void insertVector(typename std::vector<obj_t>::iterator beg, typename std::vector<obj_t>::iterator end) {
+          if (isLeaf()) {
+            while (beg != end) {
+              data.add(*beg);
+            }
+          } else {
+            for (size_t i = 0; i < n_children; ++i) {
+              typename std::vector<obj_t>::iterator mid = std::partition(beg, end, std::bind1st(intersection_test, children[i].aabb));
+              children[i].insertVector(beg, mid);
+            }
+          }
+        }
+
+        template<typename iter_t>
+        void insertMany(iter_t begin, iter_t end) {
+          if (isLeaf()) {
+          }
+        }
+
+        template<typename obj_t, typename iter_t, typename filter_t>
+        void findObjectsNear(const obj_t &object, iter_t &output, filter_t filter) {
+          if (!isLeaf()) {
+            for (size_t i = 0; i < n_children; ++i) {
+              if (intersection_test(children[i].aabb, object)) {
+                children[i].findObjectsNear(object, output, filter);
+              }
+            }
+            return;
+          }
+          data.fetch(output);
+        }
+
+        // bool hasGeometry();
+
+        // template <class T>
+        // void putInside(const T &input, Node *child, T &output);
+
+      };
+
+
+
+      Node *root;
+
+      SpatialSubdivTree(const vector_t &_min, const vector_t &_max) : root(new Node(NULL, _min, _max)) {
+      }
+
+      ~SpatialSubdivTree() {
+        delete root;
+      }
+
+      struct no_filter {
+        template<typename obj_t>
+        bool operator()(const obj_t &obj) const {
+          return true;
+        }
+      };
+
+      struct tag_filter {
+        template<typename obj_t>
+        bool operator()(const obj_t &obj) const {
+          return obj.tag_once();
+        }
+      };
+
+      // in order to be used as an input, aabb_t::intersect(const obj_t &) must exist.
+      template<typename obj_t, typename iter_t, typename filter_t>
+      void findObjectsNear(const obj_t &object, iter_t output, filter_t filter) {
+        if (!intersection_test(root->aabb, object)) return;
+        root->findObjectsNear(root, object, output, filter);
+      }
+
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/tag.hpp b/extern/carve/include/carve/tag.hpp
new file mode 100644
index 00000000000..57f9ba21460
--- /dev/null
+++ b/extern/carve/include/carve/tag.hpp
@@ -0,0 +1,44 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+namespace carve {
+
+  class tagable {
+  private:
+    static int s_count;
+
+  protected:
+    mutable int __tag;
+
+  public:
+    tagable(const tagable &) : __tag(s_count - 1) { }
+    tagable &operator=(const tagable &) { return *this; }
+
+    tagable() : __tag(s_count - 1) { }
+
+    void tag() const { __tag = s_count; }
+    void untag() const { __tag = s_count - 1; }
+    bool is_tagged() const { return __tag == s_count; }
+    bool tag_once() const { if (__tag == s_count) return false; __tag = s_count; return true; }
+
+    static void tag_begin() { s_count++; }
+  };
+}
diff --git a/extern/carve/include/carve/timing.hpp b/extern/carve/include/carve/timing.hpp
new file mode 100644
index 00000000000..f5051f72d63
--- /dev/null
+++ b/extern/carve/include/carve/timing.hpp
@@ -0,0 +1,96 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#ifndef CARVE_USE_TIMINGS
+#define CARVE_USE_TIMINGS 0
+#endif
+
+namespace carve {
+
+#if CARVE_USE_TIMINGS
+
+  class TimingName {
+  public:
+    TimingName(const char *name);
+    int id;  
+  };
+
+  class TimingBlock {
+  public:
+    /**
+     * Starts timing at the end of this constructor, using the given ID. To 
+     * associate an ID with a textual name, use Timing::registerID.
+     */
+    TimingBlock(int id);  
+    TimingBlock(const TimingName &name);
+    ~TimingBlock();
+  };
+
+  class Timing {
+  public:
+  
+    /**
+     * Starts timing against a particular ID.
+     */
+    static void start(int id);
+    
+    static void start(const TimingName &id) {
+      start(id.id);
+    }
+  
+    /**
+     * Stops the most recent timing block.
+     */
+    static double stop();
+  
+    /**
+     * This will print out the current state of recorded time blocks. It will 
+     * display the tree of timings, as well as the summaries down the bottom.
+     */
+    static void printTimings();
+    
+    /**
+     * Associates a particular ID with a text string. This is used when 
+     * printing out the timings.
+     */
+    static void registerID(int id, const char *name);
+    
+  };
+  
+#else
+
+  struct TimingName {
+    TimingName(const char *) {}
+  };
+  struct TimingBlock {
+    TimingBlock(int /* id */) {}
+    TimingBlock(const TimingName & /* name */) {}
+  };
+  struct Timing {
+    static void start(int /* id */) {}
+    static void start(const TimingName & /* id */) {}
+    static double stop() { return 0; }
+    static void printTimings() {}
+    static void registerID(int /* id */, const char * /* name */) {}
+  };
+
+#endif
+}
diff --git a/extern/carve/include/carve/tree.hpp b/extern/carve/include/carve/tree.hpp
new file mode 100644
index 00000000000..ba1bcc6e3c1
--- /dev/null
+++ b/extern/carve/include/carve/tree.hpp
@@ -0,0 +1,324 @@
+
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/matrix.hpp>
+#include <carve/timing.hpp>
+#include <carve/rescale.hpp>
+
+namespace carve {
+  namespace csg {
+
+    class CSG_TreeNode {
+      CSG_TreeNode(const CSG_TreeNode &);
+      CSG_TreeNode &operator=(const CSG_TreeNode &);
+
+    protected:
+  
+    public:
+      CSG_TreeNode() {
+      }
+
+      virtual ~CSG_TreeNode() {
+      }
+
+      virtual carve::mesh::MeshSet<3> *eval(bool &is_temp, CSG &csg) =0;
+
+      virtual carve::mesh::MeshSet<3> *eval(CSG &csg) {
+        bool temp;
+        carve::mesh::MeshSet<3> *r = eval(temp, csg);
+        if (!temp) r = r->clone();
+        return r;
+      }
+    };
+
+
+
+    class CSG_TransformNode : public CSG_TreeNode {
+      carve::math::Matrix transform;
+      CSG_TreeNode *child;
+
+    public:
+      CSG_TransformNode(const carve::math::Matrix &_transform, CSG_TreeNode *_child) : transform(_transform), child(_child) {
+      }
+      virtual ~CSG_TransformNode() {
+        delete child;
+      }
+
+      virtual carve::mesh::MeshSet<3> *eval(bool &is_temp, CSG &csg) {
+        carve::mesh::MeshSet<3> *result = child->eval(is_temp, csg);
+        if (!is_temp) {
+          result = result->clone();
+          is_temp = true;
+        }
+        result->transform(carve::math::matrix_transformation(transform));
+        return result;
+      }
+    };
+
+
+
+
+    class CSG_InvertNode : public CSG_TreeNode {
+      std::vector<bool> selected_meshes;
+      CSG_TreeNode *child;
+
+    public:
+      CSG_InvertNode(CSG_TreeNode *_child) : selected_meshes(), child(_child) {
+      }
+      CSG_InvertNode(int g_id, CSG_TreeNode *_child) : selected_meshes(), child(_child) {
+        selected_meshes.resize(g_id + 1, false);
+        selected_meshes[g_id] = true;
+      }
+      virtual ~CSG_InvertNode() {
+        delete child;
+      }
+
+      template<typename T>
+      CSG_InvertNode(T start, T end, CSG_TreeNode *_child) : selected_meshes(), child(_child) {
+        while (start != end) {
+          int g_id = (int)(*start);
+          if (selected_meshes.size() < g_id + 1) selected_meshes.resize(g_id + 1, false);
+          selected_meshes[g_id] = true;
+          ++start;
+        }
+      }
+
+      virtual carve::mesh::MeshSet<3> *eval(bool &is_temp, CSG &csg) {
+        bool c_temp;
+        carve::mesh::MeshSet<3> *c = child->eval(c_temp, csg);
+        if (!c_temp) c = c->clone();
+        if (!selected_meshes.size()) {
+          c->invert();
+        } else {
+          for (size_t i = 0; i < c->meshes.size() && i < selected_meshes.size(); ++i) {
+            if (selected_meshes[i]) {
+              c->meshes[i]->invert();
+            }
+          }
+        }
+        is_temp = true;
+        return c;
+      }
+    };
+
+
+
+
+    class CSG_SelectNode : public CSG_TreeNode {
+      std::vector<bool> selected_meshes;
+      CSG_TreeNode *child;
+
+    public:
+      CSG_SelectNode(int m_id, CSG_TreeNode *_child) : selected_meshes(), child(_child) {
+        selected_meshes.resize(m_id + 1, false);
+        selected_meshes[m_id] = true;
+      }
+
+      template<typename T>
+      CSG_SelectNode(T start, T end, CSG_TreeNode *_child) : selected_meshes(), child(_child) {
+        while (start != end) {
+          int m_id = (int)(*start);
+          if ((int)selected_meshes.size() < m_id + 1) selected_meshes.resize(m_id + 1, false);
+          selected_meshes[m_id] = true;
+          ++start;
+        }
+      }
+
+      virtual ~CSG_SelectNode() {
+        delete child;
+      }
+
+      virtual carve::mesh::MeshSet<3> *eval(bool &is_temp, CSG &csg) {
+        bool c_temp;
+        carve::mesh::MeshSet<3> *c = child->eval(c_temp, csg);
+        if (!c_temp) c = c->clone();
+        size_t i = 0;
+        size_t j = 0;
+        for (size_t i = 0; i < c->meshes.size(); ++i) {
+          if (i >= selected_meshes.size() || !selected_meshes[i]) {
+            delete c->meshes[i];
+            c->meshes[i] = NULL;
+          } else {
+            c->meshes[j++] = c->meshes[i];
+          }
+        }
+        c->meshes.erase(c->meshes.begin() + j, c->meshes.end());
+        c->collectVertices();
+        is_temp = true;
+        return c;
+      }
+    };
+
+
+
+
+    class CSG_PolyNode : public CSG_TreeNode {
+      carve::mesh::MeshSet<3> *poly;
+      bool del;
+
+    public:
+      CSG_PolyNode(carve::mesh::MeshSet<3> *_poly, bool _del) : poly(_poly), del(_del)  {
+      }
+      virtual ~CSG_PolyNode() {
+        static carve::TimingName FUNC_NAME("delete polyhedron");
+        carve::TimingBlock block(FUNC_NAME);
+    
+        if (del) {
+          delete poly;
+        }
+      }
+
+      virtual carve::mesh::MeshSet<3> *eval(bool &is_temp, CSG &csg) {
+        is_temp = false;
+        return poly;
+      }
+    };
+
+
+
+    class CSG_OPNode : public CSG_TreeNode {
+      CSG_TreeNode *left, *right;
+      CSG::OP op;
+      bool rescale;
+      CSG::CLASSIFY_TYPE classify_type;
+
+    public:
+      CSG_OPNode(CSG_TreeNode *_left,
+                 CSG_TreeNode *_right,
+                 CSG::OP _op,
+                 bool _rescale,
+                 CSG::CLASSIFY_TYPE _classify_type = CSG::CLASSIFY_NORMAL) : left(_left), right(_right), op(_op), rescale(_rescale), classify_type(_classify_type) {
+      }
+
+      virtual ~CSG_OPNode() {
+        delete left;
+        delete right;
+      }
+
+      void minmax(double &min_x, double &min_y, double &min_z,
+                  double &max_x, double &max_y, double &max_z,
+                  const std::vector<carve::geom3d::Vector> &points) {
+        for (unsigned i = 1; i < points.size(); ++i) {
+          min_x = std::min(min_x, points[i].x);
+          max_x = std::max(max_x, points[i].x);
+          min_y = std::min(min_y, points[i].y);
+          max_y = std::max(max_y, points[i].y);
+          min_z = std::min(min_z, points[i].z);
+          max_z = std::max(max_z, points[i].z);
+        }
+      }
+
+      virtual carve::mesh::MeshSet<3> *evalScaled(bool &is_temp, CSG &csg) {
+        carve::mesh::MeshSet<3> *l, *r;
+        bool l_temp, r_temp;
+
+        l = left->eval(l_temp, csg);
+        r = right->eval(r_temp, csg);
+
+        if (!l_temp) { l = l->clone(); }
+        if (!r_temp) { r = r->clone(); }
+
+        carve::geom3d::Vector min, max;
+        carve::geom3d::Vector min_l, max_l;
+        carve::geom3d::Vector min_r, max_r;
+
+        carve::geom::bounds<3>(l->vertex_storage.begin(),
+                               l->vertex_storage.end(),
+                               carve::mesh::Face<3>::vector_mapping(),
+                               min_l,
+                               max_l);
+        carve::geom::bounds<3>(r->vertex_storage.begin(),
+                               r->vertex_storage.end(),
+                               carve::mesh::Face<3>::vector_mapping(),
+                               min_r,
+                               max_r);
+
+        carve::geom::assign_op(min, min_l, min_r, carve::util::min_functor());
+        carve::geom::assign_op(max, max_l, max_r, carve::util::max_functor());
+
+        carve::rescale::rescale scaler(min.x, min.y, min.z, max.x, max.y, max.z);
+
+        carve::rescale::fwd fwd_r(scaler);
+        carve::rescale::rev rev_r(scaler);
+
+        l->transform(fwd_r);
+        r->transform(fwd_r);
+
+        carve::mesh::MeshSet<3> *result = NULL;
+        {
+          static carve::TimingName FUNC_NAME("csg.compute()");
+          carve::TimingBlock block(FUNC_NAME);
+          result = csg.compute(l, r, op, NULL, classify_type);
+        }
+
+        {
+          static carve::TimingName FUNC_NAME("delete polyhedron");
+          carve::TimingBlock block(FUNC_NAME);
+      
+          delete l;
+          delete r;
+        }
+
+        result->transform(rev_r);
+
+        is_temp = true;
+        return result;
+      }
+  
+      virtual carve::mesh::MeshSet<3> *evalUnscaled(bool &is_temp, CSG &csg) {
+        carve::mesh::MeshSet<3> *l, *r;
+        bool l_temp, r_temp;
+
+        l = left->eval(l_temp, csg);
+        r = right->eval(r_temp, csg);
+
+        carve::mesh::MeshSet<3> *result = NULL;
+        {
+          static carve::TimingName FUNC_NAME("csg.compute()");
+          carve::TimingBlock block(FUNC_NAME);
+          result = csg.compute(l, r, op, NULL, classify_type);
+        }
+
+        {
+          static carve::TimingName FUNC_NAME("delete polyhedron");
+          carve::TimingBlock block(FUNC_NAME);
+      
+          if (l_temp) delete l;
+          if (r_temp) delete r;
+        }
+
+        is_temp = true;
+        return result;
+      }
+  
+
+      virtual carve::mesh::MeshSet<3> *eval(bool &is_temp, CSG &csg) {
+        if (rescale) {
+          return evalScaled(is_temp, csg);
+        } else {
+          return evalUnscaled(is_temp, csg);
+        }
+      }
+    };
+
+  }
+}
diff --git a/extern/carve/include/carve/triangulator.hpp b/extern/carve/include/carve/triangulator.hpp
new file mode 100644
index 00000000000..aa007f98077
--- /dev/null
+++ b/extern/carve/include/carve/triangulator.hpp
@@ -0,0 +1,175 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <list>
+#include <vector>
+#include <algorithm>
+
+#include <carve/carve.hpp>
+
+#include <carve/geom2d.hpp>
+
+namespace carve {
+  namespace triangulate {
+
+    /** 
+     * \brief Merge a set of holes into a polygon. (templated)
+     *
+     * Take a polygon loop and a collection of hole loops, and patch
+     * the hole loops into the polygon loop, returning a vector of
+     * vertices from the polygon and holes, which describes a new
+     * polygon boundary with no holes. The new polygon boundary is
+     * constructed via the addition of edges * joining the polygon
+     * loop to the holes.
+     * 
+     * This may be applied to arbitrary vertex data (generally
+     * carve::geom3d::Vertex pointers), but a projection function must
+     * be supplied to convert vertices to coordinates in 2-space, in
+     * which the work is performed.
+     *
+     * @tparam project_t A functor which converts vertices to a 2d
+     *                   projection.
+     * @tparam vert_t    The vertex type.
+     * @param project The projection functor.
+     * @param f_loop The polygon loop into which holes are to be
+     *               incorporated.
+     * @param h_loops The set of hole loops to be incorporated.
+     * 
+     * @return A vector of vertex pointers.
+     */
+    template<typename project_t, typename vert_t>
+    static std::vector<vert_t>
+    incorporateHolesIntoPolygon(const project_t &project,
+                                const std::vector<vert_t> &f_loop,
+                                const std::vector<std::vector<vert_t> > &h_loops);
+
+    void
+    incorporateHolesIntoPolygon(const std::vector<std::vector<carve::geom2d::P2> > &poly,
+                                std::vector<std::pair<size_t, size_t> > &result,
+                                size_t poly_loop,
+                                const std::vector<size_t> &hole_loops);
+
+    /** 
+     * \brief Merge a set of holes into a polygon. (2d)
+     *
+     * Take a polygon loop and a collection of hole loops, and patch
+     * the hole loops into the polygon loop, returning a vector of
+     * containing the vertices from the polygon and holes which
+     * describes a new polygon boundary with no holes, through the
+     * addition of edges joining the polygon loop to the holes.
+     * 
+     * @param poly A vector containing the face loop (the first
+     *             element of poly) and the hole loops (second and
+     *             subsequent elements of poly).
+     * 
+     * @return A vector of pairs of <loop_number, index> that
+     *         reference poly and define the result polygon loop.
+     */
+    std::vector<std::pair<size_t, size_t> > incorporateHolesIntoPolygon(const std::vector<std::vector<carve::geom2d::P2> > &poly);
+
+    std::vector<std::vector<std::pair<size_t, size_t> > > mergePolygonsAndHoles(const std::vector<std::vector<carve::geom2d::P2> > &poly);
+
+
+    struct tri_idx {
+      union {
+        unsigned v[3];
+        struct { unsigned a, b, c; };
+      };
+
+      tri_idx() : a(0), b(0), c(0) {
+      }
+      tri_idx(unsigned _a, unsigned _b, unsigned _c) : a(_a), b(_b), c(_c) {
+      }
+    };
+
+    /** 
+     * \brief Triangulate a 2-dimensional polygon.
+     * 
+     * Given a 2-dimensional polygon described as a vector of 2-d
+     * points, with no holes and no self-crossings, produce a
+     * triangulation using an ear-clipping algorithm.
+     *
+     * @param [in] poly A vector containing the input polygon.
+     * @param [out] result A vector of triangles, represented as
+     *                     indicies into poly.
+     */
+
+    
+    void triangulate(const std::vector<carve::geom2d::P2> &poly, std::vector<tri_idx> &result);
+
+    /** 
+     * \brief Triangulate a polygon (templated).
+     *
+     * @tparam project_t A functor which converts vertices to a 2d
+     *                   projection.
+     * @tparam vert_t    The vertex type.
+     * @param [in] project The projection functor.
+     * @param [in] poly A vector containing the input polygon,
+     *                  represented as vert_t pointers.
+     * @param [out] result A vector of triangles, represented as
+     *                     indicies into poly.
+     */
+    template<typename project_t, typename vert_t>
+    void triangulate(const project_t &project,
+                     const std::vector<vert_t> &poly,
+                     std::vector<tri_idx> &result);
+
+    /** 
+     * \brief Improve a candidate triangulation of poly by minimising
+     * the length of internal edges. (templated)
+     *
+     * @tparam project_t A functor which converts vertices to a 2d
+     *                   projection.
+     * @tparam vert_t    The vertex type.
+     * @param [in] project The projection functor.
+     * @param [in] poly A vector containing the input polygon,
+     *                  represented as vert_t pointers.
+     * @param [inout] result A vector of triangles, represented as
+     *                       indicies into poly. On input, this vector
+     *                       must contain a candidate triangulation of
+     *                       poly. Calling improve() modifies the
+     *                       contents of the vector, returning an
+     *                       improved triangulation.
+     */
+    template<typename project_t, typename vert_t>
+    void improve(const project_t &project,
+                 const std::vector<vert_t> &poly,
+                 std::vector<tri_idx> &result);
+
+    /** 
+     * \brief Improve a candidate triangulation of poly by minimising
+     * the length of internal edges.
+     *
+     * @param [in] poly A vector containing the input polygon.
+
+     * @param [inout] result A vector of triangles, represented as
+     *                       indicies into poly. On input, this vector
+     *                       must contain a candidate triangulation of
+     *                       poly. Calling improve() modifies the
+     *                       contents of the vector, returning an
+     *                       improved triangulation.
+     */
+    static inline void improve(const std::vector<carve::geom2d::P2> &poly, std::vector<tri_idx> &result) {
+      improve(carve::geom2d::p2_adapt_ident(), poly, result);
+    }
+
+  }
+}
+
+#include <carve/triangulator_impl.hpp>
diff --git a/extern/carve/include/carve/triangulator_impl.hpp b/extern/carve/include/carve/triangulator_impl.hpp
new file mode 100644
index 00000000000..476438fd248
--- /dev/null
+++ b/extern/carve/include/carve/triangulator_impl.hpp
@@ -0,0 +1,851 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/geom2d.hpp>
+
+#if defined(CARVE_DEBUG)
+#  include <iostream>
+#endif
+
+namespace carve {
+  namespace triangulate {
+    namespace detail {
+
+
+
+      static inline bool axisOrdering(const carve::geom2d::P2 &a,
+                                      const carve::geom2d::P2 &b,
+                                      int axis) {
+          return a.v[axis] < b.v[axis] || (a.v[axis] == b.v[axis] && a.v[1-axis] < b.v[1-axis]);
+      }
+
+
+
+      /**
+       * \class order_h_loops
+       * \brief Provides an ordering of hole loops based upon a single
+       * projected axis.
+       *
+       * @tparam project_t A functor which converts vertices to a 2d
+       *                   projection.
+       * @tparam hole_t A collection of vertices.
+       */
+      template<typename project_t, typename vert_t>
+      class order_h_loops {
+        const project_t &project;
+        int axis;
+      public:
+
+        /**
+         * 
+         * @param _project The projection functor.
+         * @param _axis The axis of the 2d projection upon which hole
+         *              loops are ordered.
+         */
+        order_h_loops(const project_t &_project, int _axis) : project(_project), axis(_axis) { }
+
+        bool operator()(const vert_t &a,
+                        const vert_t &b) const {
+          return axisOrdering(project(a), project(b), axis);
+        }
+
+        bool operator()(
+            const std::pair<const typename std::vector<vert_t> *, typename std::vector<vert_t>::const_iterator> &a,
+            const std::pair<const typename std::vector<vert_t> *, typename std::vector<vert_t>::const_iterator> &b) {
+          return axisOrdering(project(*(a.second)), project(*(b.second)), axis);
+        }
+      };
+
+
+
+      /**
+       * \class heap_ordering
+       * \brief Provides an ordering of vertex indicies in a polygon
+       * loop according to proximity to a vertex.
+       *
+       * @tparam project_t A functor which converts vertices to a 2d
+       *                   projection.
+       * @tparam vert_t A vertex type.
+       */
+      template<typename project_t, typename vert_t>
+      class heap_ordering {
+        const project_t &project;
+        const std::vector<vert_t> &loop;
+        const carve::geom2d::P2 p;
+        int axis;
+
+      public:
+        /** 
+         * 
+         * @param _project A functor which converts vertices to a 2d
+         *                 projection.
+         * @param _loop The polygon loop which indices address.
+         * @param _vert The vertex from which distance is measured.
+         * 
+         */
+        heap_ordering(const project_t &_project,
+                      const std::vector<vert_t> &_loop,
+                      vert_t _vert,
+                      int _axis) :
+            project(_project),
+            loop(_loop),
+            p(_project(_vert)),
+            axis(_axis) {
+        }
+
+        bool operator()(size_t a, size_t b) const {
+          carve::geom2d::P2 pa = project(loop[a]);
+          carve::geom2d::P2 pb = project(loop[b]);
+          double da = carve::geom::distance2(p, pa);
+          double db = carve::geom::distance2(p, pb);
+          if (da > db) return true;
+          if (da < db) return false;
+          return axisOrdering(pa, pb, axis);
+        }
+      };
+
+
+
+      /** 
+       * \brief Given a polygon loop and a hole loop, and attachment
+       * points, insert the hole loop vertices into the polygon loop.
+       * 
+       * @param[in,out] f_loop The polygon loop to incorporate the
+       *                       hole into.
+       * @param f_loop_attach[in] The index of the vertex of the
+       *                          polygon loop that the hole is to be
+       *                          attached to.
+       * @param hole_attach[in] A pair consisting of a pointer to a
+       *                        hole container and an iterator into
+       *                        that container reflecting the point of
+       *                        attachment of the hole.
+       */
+      template<typename vert_t>
+      void patchHoleIntoPolygon(std::vector<vert_t> &f_loop,
+                             unsigned f_loop_attach,
+                             const std::pair<const std::vector<vert_t> *,
+                                             typename std::vector<vert_t>::const_iterator> &hole_attach) {
+        // join the vertex curr of the polygon loop to the hole at
+        // h_loop_connect
+        f_loop.insert(f_loop.begin() + f_loop_attach + 1, hole_attach.first->size() + 2, NULL);
+        typename std::vector<vert_t>::iterator f = f_loop.begin() + f_loop_attach;
+
+        typename std::vector<vert_t>::const_iterator h = hole_attach.second;
+
+        while (h != hole_attach.first->end()) {
+          *++f = *h++;
+        }
+
+        h = hole_attach.first->begin();
+        typename std::vector<vert_t>::const_iterator he = hole_attach.second; ++he;
+        while (h != he) {
+          *++f = *h++;
+        }
+
+        *++f = f_loop[f_loop_attach];
+      }
+
+
+
+      struct vertex_info;
+
+
+
+      /** 
+       * \brief Determine whether c is to the left of a->b.
+       */
+      static inline bool isLeft(const vertex_info *a,
+                                const vertex_info *b,
+                                const vertex_info *c);
+
+
+
+      /** 
+       * \brief Determine whether d is contained in the triangle abc.
+       */
+      static inline bool pointInTriangle(const vertex_info *a,
+                                         const vertex_info *b,
+                                         const vertex_info *c,
+                                         const vertex_info *d);
+
+
+
+      /**
+       * \class vertex_info
+       * \brief Maintains a linked list of untriangulated vertices
+       * during a triangulation operation.
+       */
+
+      struct vertex_info {
+        vertex_info *prev;
+        vertex_info *next;
+        carve::geom2d::P2 p;
+        size_t idx;
+        double score;
+        bool convex;
+        bool failed;
+
+        vertex_info(const carve::geom2d::P2 &_p, size_t _idx) :
+          prev(NULL), next(NULL),
+          p(_p), idx(_idx),
+          score(0.0), convex(false) {
+        }
+
+        static double triScore(const vertex_info *p, const vertex_info *v, const vertex_info *n);
+
+        double calcScore() const;
+
+        void recompute() {
+          score = calcScore();
+          convex = isLeft(prev, this, next);
+          failed = false;
+        }
+
+        bool isCandidate() const {
+          return convex && !failed;
+        }
+
+        void remove() {
+          next->prev = prev;
+          prev->next = next;
+        }
+    
+        bool isClipable() const;
+      };
+
+
+
+      static inline bool isLeft(const vertex_info *a,
+                                const vertex_info *b,
+                                const vertex_info *c) {
+        if (a->idx < b->idx && b->idx < c->idx) {
+          return carve::geom2d::orient2d(a->p, b->p, c->p) > 0.0;
+        } else if (a->idx < c->idx && c->idx < b->idx) {
+          return carve::geom2d::orient2d(a->p, c->p, b->p) < 0.0;
+        } else if (b->idx < a->idx && a->idx < c->idx) {
+          return carve::geom2d::orient2d(b->p, a->p, c->p) < 0.0;
+        } else if (b->idx < c->idx && c->idx < a->idx) {
+          return carve::geom2d::orient2d(b->p, c->p, a->p) > 0.0;
+        } else if (c->idx < a->idx && a->idx < b->idx) {
+          return carve::geom2d::orient2d(c->p, a->p, b->p) > 0.0;
+        } else {
+          return carve::geom2d::orient2d(c->p, b->p, a->p) < 0.0;
+        }
+      }
+
+
+
+      static inline bool pointInTriangle(const vertex_info *a,
+                                         const vertex_info *b,
+                                         const vertex_info *c,
+                                         const vertex_info *d) {
+        return !isLeft(a, c, d) && !isLeft(b, a, d) && !isLeft(c, b, d);
+      }
+
+
+
+      size_t removeDegeneracies(vertex_info *&begin, std::vector<carve::triangulate::tri_idx> &result);
+
+      bool splitAndResume(vertex_info *begin, std::vector<carve::triangulate::tri_idx> &result);
+
+      bool doTriangulate(vertex_info *begin, std::vector<carve::triangulate::tri_idx> &result);
+
+
+
+      typedef std::pair<unsigned, unsigned> vert_edge_t;
+
+
+
+      struct hash_vert_edge_t {
+        size_t operator()(const vert_edge_t &e) const {
+          size_t r = (size_t)e.first;
+          size_t s = (size_t)e.second;
+          return r ^ ((s >> 16) | (s << 16));
+        }
+      };
+
+
+
+      static inline vert_edge_t ordered_vert_edge_t(unsigned a, unsigned b) {
+        return (a < b) ? vert_edge_t(a, b) : vert_edge_t(b, a);
+      }
+
+
+
+      struct tri_pair_t {
+        carve::triangulate::tri_idx *a, *b;
+        double score;
+        size_t idx;
+
+        tri_pair_t() : a(NULL), b(NULL), score(0.0) {
+        }
+
+        static inline unsigned N(unsigned i) { return (i+1)%3; }
+        static inline unsigned P(unsigned i) { return (i+2)%3; }
+
+        void findSharedEdge(unsigned &ai, unsigned &bi) const {
+          if (a->v[1] == b->v[0]) { if (a->v[0] == b->v[1]) { ai = 0; bi = 0; } else { ai = 1; bi = 2; } return; }
+          if (a->v[1] == b->v[1]) { if (a->v[0] == b->v[2]) { ai = 0; bi = 1; } else { ai = 1; bi = 0; } return; }
+          if (a->v[1] == b->v[2]) { if (a->v[0] == b->v[0]) { ai = 0; bi = 2; } else { ai = 1; bi = 1; } return; }
+          if (a->v[2] == b->v[0]) { ai = 2; bi = 2; return; }
+          if (a->v[2] == b->v[1]) { ai = 2; bi = 0; return; }
+          if (a->v[2] == b->v[2]) { ai = 2; bi = 1; return; }
+          CARVE_FAIL("should not be reached");
+        }
+
+        void flip(vert_edge_t &old_edge,
+                  vert_edge_t &new_edge,
+                  vert_edge_t perim[4]);
+
+        template<typename project_t, typename vert_t, typename distance_calc_t>
+        double calc(const project_t &project,
+                    const std::vector<vert_t> &poly,
+                    distance_calc_t dist) {
+          unsigned ai, bi;
+          unsigned cross_ai, cross_bi;
+          unsigned ea, eb;
+
+          findSharedEdge(ai, bi);
+
+#if defined(CARVE_DEBUG)
+          if (carve::geom2d::signedArea(project(poly[a->v[0]]), project(poly[a->v[1]]), project(poly[a->v[2]])) > 0.0 ||
+              carve::geom2d::signedArea(project(poly[b->v[0]]), project(poly[b->v[1]]), project(poly[b->v[2]])) > 0.0) {
+            std::cerr << "warning: triangle pair " << this << " contains triangles with incorrect orientation" << std::endl;
+          }
+#endif
+
+          cross_ai = P(ai);
+          cross_bi = P(bi);
+
+          ea = a->v[cross_ai];
+          eb = b->v[cross_bi];
+
+          double side_1 = carve::geom2d::orient2d(project(poly[ea]), project(poly[eb]), project(poly[a->v[ai]]));
+          double side_2 = carve::geom2d::orient2d(project(poly[ea]), project(poly[eb]), project(poly[a->v[N(ai)]]));
+
+          bool can_flip = (side_1 < 0.0 && side_2 > 0.0) || (side_1 > 0.0 && side_2 < 0.0);
+
+          if (!can_flip) {
+            score = -1;
+          } else {
+            score =
+              dist(poly[a->v[ai]], poly[b->v[bi]]) -
+              dist(poly[a->v[cross_ai]], poly[b->v[cross_bi]]);
+          }
+          return score;
+        }
+
+        template<typename project_t, typename vert_t, typename distance_calc_t>
+        double edgeLen(const project_t &project,
+                       const std::vector<vert_t> &poly,
+                       distance_calc_t dist) const {
+          unsigned ai, bi;
+          findSharedEdge(ai, bi);
+          return dist(poly[a->v[ai]], poly[b->v[bi]]);
+        }
+      };
+
+
+
+      struct max_score {
+        bool operator()(const tri_pair_t *a, const tri_pair_t *b) const { return a->score < b->score; }
+      };
+
+
+
+      struct tri_pairs_t {
+        typedef std::unordered_map<vert_edge_t, tri_pair_t *, hash_vert_edge_t> storage_t;
+        storage_t storage;
+
+        tri_pairs_t() : storage() {
+        };
+
+        ~tri_pairs_t() {
+          for (storage_t::iterator i = storage.begin(); i != storage.end(); ++i) {
+            if ((*i).second) delete (*i).second;
+          }
+        }
+
+        void insert(unsigned a, unsigned b, carve::triangulate::tri_idx *t);
+
+        template<typename project_t, typename vert_t, typename distance_calc_t>
+        void updateEdge(tri_pair_t *tp,
+                        const project_t &project,
+                        const std::vector<vert_t> &poly,
+                        distance_calc_t dist,
+                        std::vector<tri_pair_t *> &edges,
+                        size_t &n) {
+          double old_score = tp->score;
+          double new_score = tp->calc(project, poly, dist);
+#if defined(CARVE_DEBUG)
+          std::cerr << "tp:" << tp << " old_score: " << old_score << " new_score: " << new_score << std::endl;
+#endif
+          if (new_score > 0.0 && old_score <= 0.0) {
+            tp->idx = n;
+            edges[n++] = tp;
+          } else if (new_score <= 0.0 && old_score > 0.0) {
+            std::swap(edges[tp->idx], edges[--n]);
+            edges[tp->idx]->idx = tp->idx;
+          }
+        }
+
+        tri_pair_t *get(vert_edge_t &e) {
+          storage_t::iterator i;
+          i = storage.find(e);
+          if (i == storage.end()) return NULL;
+          return (*i).second;
+        }
+
+        template<typename project_t, typename vert_t, typename distance_calc_t>
+        void flip(const project_t &project,
+                  const std::vector<vert_t> &poly,
+                  distance_calc_t dist,
+                  std::vector<tri_pair_t *> &edges,
+                  size_t &n) {
+          vert_edge_t old_e, new_e;
+          vert_edge_t perim[4];
+
+#if defined(CARVE_DEBUG)
+          std::cerr << "improvable edges: " << n << std::endl;
+#endif
+
+          tri_pair_t *tp = *std::max_element(edges.begin(), edges.begin() + n, max_score());
+
+#if defined(CARVE_DEBUG)
+          std::cerr << "improving tri-pair: " << tp << " with score: " << tp->score << std::endl;
+#endif
+
+          tp->flip(old_e, new_e, perim);
+
+#if defined(CARVE_DEBUG)
+          std::cerr << "old_e: " << old_e.first << "," << old_e.second << " -> new_e: " << new_e.first << "," << new_e.second << std::endl;
+#endif
+
+          CARVE_ASSERT(storage.find(old_e) != storage.end());
+          storage.erase(old_e);
+          storage[new_e] = tp;
+
+          std::swap(edges[tp->idx], edges[--n]);
+          edges[tp->idx]->idx = tp->idx;
+
+          tri_pair_t *tp2;
+
+          tp2 = get(perim[0]);
+          if (tp2 != NULL) {
+            updateEdge(tp2, project, poly, dist, edges, n);
+          }
+
+          tp2 = get(perim[1]);
+          if (tp2 != NULL) {
+            CARVE_ASSERT(tp2->a == tp->b || tp2->b == tp->b);
+            if (tp2->a == tp->b) { tp2->a = tp->a; } else { tp2->b = tp->a; }
+            updateEdge(tp2, project, poly, dist, edges, n);
+          }
+
+          tp2 = get(perim[2]);
+          if (tp2 != NULL) {
+            updateEdge(tp2, project, poly, dist, edges, n);
+          }
+
+          tp2 = get(perim[3]);
+          if (tp2 != NULL) {
+            CARVE_ASSERT(tp2->a == tp->a || tp2->b == tp->a);
+            if (tp2->a == tp->a) { tp2->a = tp->b; } else { tp2->b = tp->b; }
+            updateEdge(tp2, project, poly, dist, edges, n);
+          }
+        }
+
+        template<typename project_t, typename vert_t, typename distance_calc_t>
+        size_t getInternalEdges(const project_t &project,
+                                const std::vector<vert_t> &poly,
+                                distance_calc_t dist,
+                                std::vector<tri_pair_t *> &edges) {
+          size_t count = 0;
+
+          for (storage_t::iterator i = storage.begin(); i != storage.end();) {
+            tri_pair_t *tp = (*i).second;
+            if (tp->a && tp->b) {
+              tp->calc(project, poly, dist);
+              count++;
+#if defined(CARVE_DEBUG)
+              std::cerr << "internal edge: " << (*i).first.first << "," << (*i).first.second << " -> " << tp << " " << tp->score << std::endl;
+#endif
+              ++i;
+            } else {
+              delete (*i).second;
+              storage.erase(i++);
+            }
+          }
+
+          edges.resize(count);
+
+          size_t fwd = 0;
+          size_t rev = count;
+          for (storage_t::iterator i = storage.begin(); i != storage.end(); ++i) {
+            tri_pair_t *tp = (*i).second;
+            if (tp && tp->a && tp->b) {
+              if (tp->score > 0.0) {
+                edges[fwd++] = tp;
+              } else {
+                edges[--rev] = tp;
+              }
+            }
+          }
+
+          CARVE_ASSERT(fwd == rev);
+
+          return fwd;
+        }
+      };
+
+
+
+      template<typename project_t, typename vert_t>
+      static bool
+      testCandidateAttachment(const project_t &project,
+                              std::vector<vert_t> &current_f_loop,
+                              size_t curr,
+                              carve::geom2d::P2 hole_min) {
+        const size_t SZ = current_f_loop.size();
+
+        size_t prev, next;
+
+        if (curr == 0) {
+          prev = SZ - 1; next = 1;
+        } else if (curr == SZ - 1) {
+          prev = curr - 1; next = 0;
+        } else {
+          prev = curr - 1; next = curr + 1;
+        }
+
+        if (!carve::geom2d::internalToAngle(project(current_f_loop[next]),
+                                            project(current_f_loop[curr]),
+                                            project(current_f_loop[prev]),
+                                            hole_min)) {
+          return false;
+        }
+
+        if (hole_min == project(current_f_loop[curr])) {
+          return true;
+        }
+
+        carve::geom2d::LineSegment2 test(hole_min, project(current_f_loop[curr]));
+
+        size_t v1 = current_f_loop.size() - 1;
+        size_t v2 = 0;
+        double v1_side = carve::geom2d::orient2d(test.v1, test.v2, project(current_f_loop[v1]));
+        double v2_side = 0;
+
+        while (v2 != current_f_loop.size()) {
+          v2_side = carve::geom2d::orient2d(test.v1, test.v2, project(current_f_loop[v2]));
+
+          if (v1_side != v2_side) {
+            // XXX: need to test vertices, not indices, because they may
+            // be duplicated.
+            if (project(current_f_loop[v1]) != project(current_f_loop[curr]) &&
+                project(current_f_loop[v2]) != project(current_f_loop[curr])) {
+              carve::geom2d::LineSegment2 test2(project(current_f_loop[v1]), project(current_f_loop[v2]));
+              if (carve::geom2d::lineSegmentIntersection_simple(test, test2)) {
+                // intersection; failed.
+                return false;
+              }
+            }
+          }
+
+          v1 = v2;
+          v1_side = v2_side;
+          ++v2;
+        }
+        return true;
+      }
+
+
+
+    }
+
+
+
+    template<typename project_t, typename vert_t>
+    static std::vector<vert_t>
+    incorporateHolesIntoPolygon(const project_t &project,
+                                const std::vector<vert_t> &f_loop,
+                                const std::vector<std::vector<vert_t> > &h_loops) {
+      typedef std::vector<vert_t> hole_t;
+      typedef typename std::vector<vert_t>::const_iterator vert_iter;
+      typedef typename std::vector<std::vector<vert_t> >::const_iterator hole_iter;
+
+      size_t N = f_loop.size();
+
+      // work out how much space to reserve for the patched in holes.
+      for (hole_iter i = h_loops.begin(); i != h_loops.end(); ++i) {
+        N += 2 + (*i).size();
+      }
+    
+      // this is the vector that we will build the result in.
+      std::vector<vert_t> current_f_loop;
+      current_f_loop.reserve(N);
+
+      std::vector<size_t> f_loop_heap;
+      f_loop_heap.reserve(N);
+
+      for (unsigned i = 0; i < f_loop.size(); ++i) {
+        current_f_loop.push_back(f_loop[i]);
+      }
+
+      std::vector<std::pair<const std::vector<vert_t> *, vert_iter> > h_loop_min_vertex;
+
+      h_loop_min_vertex.reserve(h_loops.size());
+
+      // find the major axis for the holes - this is the axis that we
+      // will sort on for finding vertices on the polygon to join
+      // holes up to.
+      //
+      // it might also be nice to also look for whether it is better
+      // to sort ascending or descending.
+      // 
+      // another trick that could be used is to modify the projection
+      // by 90 degree rotations or flipping about an axis. just as
+      // long as we keep the carve::geom3d::Vector pointers for the
+      // real data in sync, everything should be ok. then we wouldn't
+      // need to accomodate axes or sort order in the main loop.
+
+      // find the bounding box of all the holes.
+      bool first = true;
+      double min_x, min_y, max_x, max_y;
+      for (hole_iter i = h_loops.begin(); i != h_loops.end(); ++i) {
+        const hole_t &hole(*i);
+        for (vert_iter j = hole.begin(); j != hole.end(); ++j) {
+          carve::geom2d::P2 curr = project(*j);
+          if (first) {
+            min_x = max_x = curr.x;
+            min_y = max_y = curr.y;
+            first = false;
+          } else {
+            min_x = std::min(min_x, curr.x);
+            min_y = std::min(min_y, curr.y);
+            max_x = std::max(max_x, curr.x);
+            max_y = std::max(max_y, curr.y);
+          }
+        }
+      }
+
+      // choose the axis for which the bbox is largest.
+      int axis = (max_x - min_x) > (max_y - min_y) ? 0 : 1;
+
+      // for each hole, find the minimum vertex in the chosen axis.
+      for (hole_iter i = h_loops.begin(); i != h_loops.end(); ++i) {
+        const hole_t &hole = *i;
+        vert_iter best_i = std::min_element(hole.begin(), hole.end(), detail::order_h_loops<project_t, vert_t>(project, axis));
+        h_loop_min_vertex.push_back(std::make_pair(&hole, best_i));
+      }
+
+      // sort the holes by the minimum vertex.
+      std::sort(h_loop_min_vertex.begin(), h_loop_min_vertex.end(), detail::order_h_loops<project_t, vert_t>(project, axis));
+
+      // now, for each hole, find a vertex in the current polygon loop that it can be joined to.
+      for (unsigned i = 0; i < h_loop_min_vertex.size(); ++i) {
+        const size_t N_f_loop = current_f_loop.size();
+
+        // the index of the vertex in the hole to connect.
+        vert_iter h_loop_connect = h_loop_min_vertex[i].second;
+
+        carve::geom2d::P2 hole_min = project(*h_loop_connect);
+
+        f_loop_heap.clear();
+        // we order polygon loop vertices that may be able to be connected
+        // to the hole vertex by their distance to the hole vertex
+        detail::heap_ordering<project_t, vert_t> _heap_ordering(project, current_f_loop, *h_loop_connect, axis);
+
+        for (size_t j = 0; j < N_f_loop; ++j) {
+          // it is guaranteed that there exists a polygon vertex with
+          // coord < the min hole coord chosen, which can be joined to
+          // the min hole coord without crossing the polygon
+          // boundary. also, because we merge holes in ascending
+          // order, it is also true that this join can never cross
+          // another hole (and that doesn't need to be tested for).
+          if (project(current_f_loop[j]).v[axis] <= hole_min.v[axis]) {
+            f_loop_heap.push_back(j);
+            std::push_heap(f_loop_heap.begin(), f_loop_heap.end(), _heap_ordering);
+          }
+        }
+
+        // we are going to test each potential (according to the
+        // previous test) polygon vertex as a candidate join. we order
+        // by closeness to the hole vertex, so that the join we make
+        // is as small as possible. to test, we need to check the
+        // joining line segment does not cross any other line segment
+        // in the current polygon loop (excluding those that have the
+        // vertex that we are attempting to join with as an endpoint).
+        size_t attachment_point = current_f_loop.size();
+
+        while (f_loop_heap.size()) {
+          std::pop_heap(f_loop_heap.begin(), f_loop_heap.end(), _heap_ordering);
+          size_t curr = f_loop_heap.back();
+          f_loop_heap.pop_back();
+          // test the candidate join from current_f_loop[curr] to hole_min
+
+          if (!detail::testCandidateAttachment(project, current_f_loop, curr, hole_min)) {
+            continue;
+          }
+
+          attachment_point = curr;
+          break;
+        }
+
+        if (attachment_point == current_f_loop.size()) {
+          CARVE_FAIL("didn't manage to link up hole!");
+        }
+
+        detail::patchHoleIntoPolygon(current_f_loop, attachment_point, h_loop_min_vertex[i]);
+      }
+
+      return current_f_loop;
+    }
+
+
+
+    template<typename project_t, typename vert_t>
+    void triangulate(const project_t &project,
+                     const std::vector<vert_t> &poly,
+                     std::vector<tri_idx> &result) {
+      std::vector<detail::vertex_info *> vinfo;
+      const size_t N = poly.size();
+
+      result.clear();
+      if (N < 3) {
+        return;
+      }
+
+      result.reserve(poly.size() - 2);
+
+      if (N == 3) {
+        result.push_back(tri_idx(0, 1, 2));
+        return;
+      }
+
+      vinfo.resize(N);
+
+      vinfo[0] = new detail::vertex_info(project(poly[0]), 0);
+      for (size_t i = 1; i < N-1; ++i) {
+        vinfo[i] = new detail::vertex_info(project(poly[i]), i);
+        vinfo[i]->prev = vinfo[i-1];
+        vinfo[i-1]->next = vinfo[i];
+      }
+      vinfo[N-1] = new detail::vertex_info(project(poly[N-1]), N-1);
+      vinfo[N-1]->prev = vinfo[N-2];
+      vinfo[N-1]->next = vinfo[0];
+      vinfo[0]->prev = vinfo[N-1];
+      vinfo[N-2]->next = vinfo[N-1];
+
+      for (size_t i = 0; i < N; ++i) {
+        vinfo[i]->recompute();
+      }
+
+      detail::vertex_info *begin = vinfo[0];
+
+      removeDegeneracies(begin, result);
+      doTriangulate(begin, result);
+    }
+
+
+
+    template<typename project_t, typename vert_t, typename distance_calc_t>
+    void improve(const project_t &project,
+                 const std::vector<vert_t> &poly,
+                 distance_calc_t dist,
+                 std::vector<tri_idx> &result) {
+      detail::tri_pairs_t tri_pairs;
+
+#if defined(CARVE_DEBUG)
+      bool warn = false;
+      for (size_t i = 0; i < result.size(); ++i) {
+        tri_idx &t = result[i];
+        if (carve::geom2d::signedArea(project(poly[t.a]), project(poly[t.b]), project(poly[t.c])) > 0) {
+          warn = true;
+        }
+      } 
+      if (warn) {
+        std::cerr << "carve::triangulate::improve(): Some triangles are incorrectly oriented. Results may be incorrect." << std::endl;
+      }
+#endif
+
+      for (size_t i = 0; i < result.size(); ++i) {
+        tri_idx &t = result[i];
+        tri_pairs.insert(t.a, t.b, &t);
+        tri_pairs.insert(t.b, t.c, &t);
+        tri_pairs.insert(t.c, t.a, &t);
+      }
+
+      std::vector<detail::tri_pair_t *> edges;
+      size_t n = tri_pairs.getInternalEdges(project, poly, dist, edges);
+      for (size_t i = 0; i < n; ++i) {
+        edges[i]->idx = i;
+      }
+
+      // procedure:
+      // while a tri pair with a positive score exists:
+      //   p = pair with highest positive score
+      //   flip p, rewriting its two referenced triangles.
+      //   negate p's score
+      //   for each q in the up-to-four adjoining tri pairs:
+      //     update q's tri ptr, if changed, and its score.
+
+#if defined(CARVE_DEBUG)
+      double initial_score = 0;
+      for (size_t i = 0; i < edges.size(); ++i) {
+        initial_score += edges[i]->edgeLen(project, poly, dist);
+      }
+      std::cerr << "initial score: " << initial_score << std::endl;
+#endif
+
+      while (n) {
+        tri_pairs.flip(project, poly, dist, edges, n);
+      }
+
+#if defined(CARVE_DEBUG)
+      double final_score = 0;
+      for (size_t i = 0; i < edges.size(); ++i) {
+        final_score += edges[i]->edgeLen(project, poly, dist);
+      }
+      std::cerr << "final score: " << final_score << std::endl;
+#endif
+
+#if defined(CARVE_DEBUG)
+      if (!warn) {
+        for (size_t i = 0; i < result.size(); ++i) {
+          tri_idx &t = result[i];
+          CARVE_ASSERT (carve::geom2d::signedArea(project(poly[t.a]), project(poly[t.b]), project(poly[t.c])) <= 0.0);
+        } 
+      }
+#endif
+    }
+
+
+
+    template<typename project_t, typename vert_t>
+    void improve(const project_t &project,
+                 const std::vector<vert_t> &poly,
+                 std::vector<tri_idx> &result) {
+      improve(project, poly, carve::geom::distance_functor(), result);
+    }
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/util.hpp b/extern/carve/include/carve/util.hpp
new file mode 100644
index 00000000000..dc33f5b64ce
--- /dev/null
+++ b/extern/carve/include/carve/util.hpp
@@ -0,0 +1,31 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+namespace carve {
+  namespace util {
+    struct min_functor {
+      template<typename T>
+      const T &operator()(const T &a, const T &b) const { return std::min(a, b); }
+    };
+    struct max_functor {
+      template<typename T>
+      const T &operator()(const T &a, const T &b) const { return std::max(a, b); }
+    };
+  }
+}
diff --git a/extern/carve/include/carve/vcpp_config.h b/extern/carve/include/carve/vcpp_config.h
new file mode 100644
index 00000000000..5ebd4006159
--- /dev/null
+++ b/extern/carve/include/carve/vcpp_config.h
@@ -0,0 +1,17 @@
+/* include/carve/config.h.  Generated from config.h.in by configure.  */
+#pragma once
+
+#include <math.h>
+
+/* Define if using boost collections. Preferred, because the visual C++ unordered collections are slow and memory hungry. */
+#define HAVE_BOOST_UNORDERED_COLLECTIONS 
+
+#if defined(_MSC_VER)
+#  pragma warning(disable:4201)
+#endif
+
+#include <math.h>
+
+static inline double round(double value) {
+  return (value >= 0) ? floor(value + 0.5) : ceil(value - 0.5);
+}
diff --git a/extern/carve/include/carve/vector.hpp b/extern/carve/include/carve/vector.hpp
new file mode 100644
index 00000000000..6753ddb85d4
--- /dev/null
+++ b/extern/carve/include/carve/vector.hpp
@@ -0,0 +1,163 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/math_constants.hpp>
+#include <carve/geom.hpp>
+#include <carve/geom3d.hpp>
+
+#include <sstream>
+#include <algorithm>
+
+#include <math.h>
+
+namespace carve {
+  namespace geom3d {
+
+    struct hash_vector_ptr {
+      size_t operator()(const Vector * const &v) const {
+        return (size_t)v;
+      }
+      size_t operator()(const std::pair<const Vector *, const Vector *> &v) const {
+        size_t r = (size_t)v.first;
+        size_t s = (size_t)v.second;
+        return r ^ ((s >> 16) | (s << 16));
+      }
+    };
+
+
+
+    struct vec_adapt_ident {
+      const Vector &operator()(const Vector &v) const { return v; }
+      Vector &operator()(Vector &v) const { return v; }
+    };
+
+
+
+    struct vec_adapt_ptr {
+      const Vector &operator()(const Vector * const &v) const { return *v; }
+      Vector &operator()(Vector *&v) const { return *v; }
+    };
+
+
+  
+    struct vec_adapt_pair_first {
+      template<typename pair_t> const Vector &operator()(const pair_t &v) const { return v.first; }
+      template<typename pair_t> Vector &operator()(pair_t &v) const { return v.first; }
+    };
+
+
+
+    struct vec_adapt_pair_second {
+      template<typename pair_t> const Vector &operator()(const pair_t &v) const { return v.second; }
+      template<typename pair_t> Vector &operator()(pair_t &v) const { return v.second; }
+    };
+
+
+
+    template<typename adapt_t>
+    struct vec_cmp_lt_x {
+      adapt_t adapt;
+      vec_cmp_lt_x(adapt_t _adapt = adapt_t()) : adapt(_adapt) {}
+      template<typename input_t> bool operator()(const input_t &a, const input_t &b) const { return adapt(a).x < adapt(b).x; }
+    };
+    template<typename adapt_t> vec_cmp_lt_x<adapt_t> vec_lt_x(adapt_t &adapt) { return vec_cmp_lt_x<adapt_t>(adapt); }
+
+
+
+    template<typename adapt_t>
+    struct vec_cmp_lt_y {
+      adapt_t adapt;
+      vec_cmp_lt_y(adapt_t _adapt = adapt_t()) : adapt(_adapt) {}
+      template<typename input_t> bool operator()(const input_t &a, const input_t &b) const { return adapt(a).y < adapt(b).y; }
+    };
+    template<typename adapt_t> vec_cmp_lt_y<adapt_t> vec_lt_y(adapt_t &adapt) { return vec_cmp_lt_y<adapt_t>(adapt); }
+
+
+
+    template<typename adapt_t>
+    struct vec_cmp_lt_z {
+      adapt_t adapt;
+      vec_cmp_lt_z(adapt_t _adapt = adapt_t()) : adapt(_adapt) {}
+      template<typename input_t> bool operator()(const input_t &a, const input_t &b) const { return adapt(a).z < adapt(b).z; }
+    };
+    template<typename adapt_t> vec_cmp_lt_z<adapt_t> vec_lt_z(adapt_t &adapt) { return vec_cmp_lt_z<adapt_t>(adapt); }
+
+
+
+    template<typename adapt_t>
+    struct vec_cmp_gt_x {
+      adapt_t adapt;
+      vec_cmp_gt_x(adapt_t _adapt = adapt_t()) : adapt(_adapt) {}
+      template<typename input_t> bool operator()(const input_t &a, const input_t &b) const { return adapt(a).x > adapt(b).x; }
+    };
+    template<typename adapt_t> vec_cmp_gt_x<adapt_t> vec_gt_x(adapt_t &adapt) { return vec_cmp_gt_x<adapt_t>(adapt); }
+
+
+
+    template<typename adapt_t>
+    struct vec_cmp_gt_y {
+      adapt_t adapt;
+      vec_cmp_gt_y(adapt_t _adapt = adapt_t()) : adapt(_adapt) {}
+      template<typename input_t> bool operator()(const input_t &a, const input_t &b) const { return adapt(a).y > adapt(b).y; }
+    };
+    template<typename adapt_t> vec_cmp_gt_y<adapt_t> vec_gt_y(adapt_t &adapt) { return vec_cmp_gt_y<adapt_t>(adapt); }
+
+
+
+    template<typename adapt_t>
+    struct vec_cmp_gt_z {
+      adapt_t adapt;
+      vec_cmp_gt_z(adapt_t _adapt = adapt_t()) : adapt(_adapt) {}
+      template<typename input_t> bool operator()(const input_t &a, const input_t &b) const { return adapt(a).z > adapt(b).z; }
+    };
+    template<typename adapt_t> vec_cmp_gt_z<adapt_t> vec_gt_z(adapt_t &adapt) { return vec_cmp_gt_z<adapt_t>(adapt); }
+
+
+
+    template<typename iter_t, typename adapt_t>
+    void sortInDirectionOfRay(const Vector &ray_dir, iter_t begin, iter_t end, adapt_t adapt) {
+      switch (carve::geom::largestAxis(ray_dir)) {
+      case 0:
+        if (ray_dir.x > 0) {
+          std::sort(begin, end, vec_lt_x(adapt));
+        } else {
+          std::sort(begin, end, vec_gt_x(adapt));
+        }
+        break;
+      case 1:
+        if (ray_dir.y > 0) {
+          std::sort(begin, end, vec_lt_y(adapt));
+        } else {
+          std::sort(begin, end, vec_gt_y(adapt));
+        }
+        break;
+      case 2:
+        if (ray_dir.z > 0) {
+          std::sort(begin, end, vec_lt_z(adapt));
+        } else {
+          std::sort(begin, end, vec_gt_z(adapt));
+        }
+        break;
+      }
+    }
+
+  }
+}
diff --git a/extern/carve/include/carve/vertex_decl.hpp b/extern/carve/include/carve/vertex_decl.hpp
new file mode 100644
index 00000000000..62c76473020
--- /dev/null
+++ b/extern/carve/include/carve/vertex_decl.hpp
@@ -0,0 +1,111 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+#include <carve/carve.hpp>
+
+#include <carve/geom2d.hpp>
+#include <carve/vector.hpp>
+#include <carve/matrix.hpp>
+#include <carve/geom3d.hpp>
+#include <carve/aabb.hpp>
+#include <carve/tag.hpp>
+
+#include <vector>
+#include <list>
+#include <map>
+
+namespace carve {
+  namespace poly {
+
+
+
+    struct Object;
+
+
+
+    template<unsigned ndim>
+    class Vertex : public tagable {
+    public:
+      typedef carve::geom::vector<ndim> vector_t;
+      typedef Object obj_t;
+
+      vector_t v;
+      obj_t *owner;
+
+      Vertex() : tagable(), v() {
+      }
+
+      ~Vertex() {
+      }
+
+      Vertex(const vector_t &_v) : tagable(), v(_v) {
+      }
+    };
+
+
+
+    struct hash_vertex_ptr {
+      template<unsigned ndim>
+      size_t operator()(const Vertex<ndim> * const &v) const {
+        return (size_t)v;
+      }
+
+      template<unsigned ndim>
+      size_t operator()(const std::pair<const Vertex<ndim> *, const Vertex<ndim> *> &v) const {
+        size_t r = (size_t)v.first;
+        size_t s = (size_t)v.second;
+        return r ^ ((s >> 16) | (s << 16));
+      }
+
+    };
+
+
+
+    template<unsigned ndim>
+    double distance(const Vertex<ndim> *v1, const Vertex<ndim> *v2) {
+      return distance(v1->v, v2->v);
+    }
+
+    template<unsigned ndim>
+    double distance(const Vertex<ndim> &v1, const Vertex<ndim> &v2) {
+      return distance(v1.v, v2.v);
+    }
+
+    struct vec_adapt_vertex_ref {
+      template<unsigned ndim>
+      const typename Vertex<ndim>::vector_t &operator()(const Vertex<ndim> &v) const { return v.v; }
+
+      template<unsigned ndim>
+      typename Vertex<ndim>::vector_t &operator()(Vertex<ndim> &v) const { return v.v; }
+    };
+
+
+
+    struct vec_adapt_vertex_ptr {
+      template<unsigned ndim>
+      const typename Vertex<ndim>::vector_t &operator()(const Vertex<ndim> *v) const { return v->v; }
+
+      template<unsigned ndim>
+      typename Vertex<ndim>::vector_t &operator()(Vertex<ndim> *v) const { return v->v; }
+    };
+
+
+
+  }
+}
diff --git a/extern/carve/include/carve/vertex_impl.hpp b/extern/carve/include/carve/vertex_impl.hpp
new file mode 100644
index 00000000000..7e1803ae89c
--- /dev/null
+++ b/extern/carve/include/carve/vertex_impl.hpp
@@ -0,0 +1,24 @@
+// Begin License:
+// Copyright (C) 2006-2011 Tobias Sargeant (tobias.sargeant@gmail.com).
+// All rights reserved.
+//
+// This file is part of the Carve CSG Library (http://carve-csg.com/)
+//
+// This file may be used under the terms of the GNU General Public
+// License version 2.0 as published by the Free Software Foundation
+// and appearing in the file LICENSE.GPL2 included in the packaging of
+// this file.
+//
+// This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+// INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE.
+// End:
+
+
+#pragma once
+
+namespace carve {
+  namespace poly {
+
+  }
+}
diff --git a/extern/carve/include/carve/win32.h b/extern/carve/include/carve/win32.h
new file mode 100755
index 00000000000..b73c9535f52
--- /dev/null
+++ b/extern/carve/include/carve/win32.h
@@ -0,0 +1,53 @@
+// Copyright 2006 Tobias Sargeant (toby@permuted.net)
+// All rights reserved.
+#pragma once
+
+#pragma warning (disable : 4996)
+#pragma warning (disable : 4786)
+
+#include <string.h>
+#include <stdlib.h>
+
+inline int strcasecmp(const char *a, const char *b) {
+  return _stricmp(a,b);
+}
+
+inline void srandom(unsigned long input) {
+  srand(input);
+}
+
+inline long random() {
+  return rand();
+}
+
+#if defined(_MSC_VER)
+#  include <carve/cbrt.h>
+
+#if _MSC_VER < 1300
+// intptr_t is an integer type that is big enough to hold a pointer
+// It is not defined in VC6 so include a definition here for the older compiler
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+#endif
+
+#  if _MSC_VER < 1600
+// stdint.h is not available before VS2010
+#if defined(_WIN32) && !defined(__MINGW32__)
+/* The __intXX are built-in types of the visual complier! So we don't
+   need to include anything else here.
+   This typedefs should be in sync with types from MEM_sys_types.h */
+
+typedef signed __int8  int8_t;
+typedef signed __int16 int16_t;
+typedef signed __int32 int32_t;
+
+typedef unsigned __int8  uint8_t;
+typedef unsigned __int16 uint16_t;
+typedef unsigned __int32 uint32_t;
+#endif
+typedef __int64 int64_t;
+typedef unsigned __int64 uint64_t;
+#  else
+#    include <stdint.h>
+#  endif
+#endif