Merge branch 'blender-v2.92-release'

13 files changed, 221 insertions, 26 deletions

diff --git a/extern/mantaflow/preprocessed/fileio/iogrids.cpp b/extern/mantaflow/preprocessed/fileio/iogrids.cpp
index 7cedbb484ba..d138cd2925f 100644
--- a/extern/mantaflow/preprocessed/fileio/iogrids.cpp
+++ b/extern/mantaflow/preprocessed/fileio/iogrids.cpp
@@ -628,13 +628,24 @@ template<class T> int readGridUni(const string &name, Grid<T> *grid)
     // current file format
     UniHeader head;
     assertMsg(gzread(gzf, &head, sizeof(UniHeader)) == sizeof(UniHeader),
-              "can't read file, no header present");
-    assertMsg(head.dimX == grid->getSizeX() && head.dimY == grid->getSizeY() &&
-                  head.dimZ == grid->getSizeZ(),
-              "grid dim doesn't match, " << Vec3(head.dimX, head.dimY, head.dimZ) << " vs "
-                                         << grid->getSize());
+              "readGridUni: Can't read file, no header present");
     assertMsg(unifyGridType(head.gridType) == unifyGridType(grid->getType()),
-              "grid type doesn't match " << head.gridType << " vs " << grid->getType());
+              "readGridUni: Grid type doesn't match " << head.gridType << " vs "
+                                                      << grid->getType());
+
+    const Vec3i curGridSize = grid->getParent()->getGridSize();
+    const Vec3i headGridSize(head.dimX, head.dimY, head.dimZ);
+#  if BLENDER
+    // Correct grid size is only a soft requirement in Blender
+    if (headGridSize != curGridSize) {
+      debMsg("readGridUni: Grid dim doesn't match, " << headGridSize << " vs " << curGridSize, 1);
+      return 0;
+    }
+#  else
+    assertMsg(headGridSize == curGridSize,
+              "readGridUni: Grid dim doesn't match, " << headGridSize << " vs " << curGridSize);
+#  endif
+
 #  if FLOATINGPOINT_PRECISION != 1
     // convert float to double
     Grid<T> temp(grid->getParent());
diff --git a/extern/mantaflow/preprocessed/fileio/ioparticles.cpp b/extern/mantaflow/preprocessed/fileio/ioparticles.cpp
index 36e10aa1644..538d42f3d87 100644
--- a/extern/mantaflow/preprocessed/fileio/ioparticles.cpp
+++ b/extern/mantaflow/preprocessed/fileio/ioparticles.cpp
@@ -230,6 +230,19 @@ int readParticlesUni(const std::string &name, BasicParticleSystem *parts)
     assertMsg(((head.bytesPerElement == PartSysSize) && (head.elementType == 0)),
               "particle type doesn't match");
 
+    const Vec3i curGridSize = parts->getParent()->getGridSize();
+    const Vec3i headGridSize(head.dimX, head.dimY, head.dimZ);
+#  if BLENDER
+    // Correct grid size is only a soft requirement in Blender
+    if (headGridSize != curGridSize) {
+      debMsg("readPdataUni: Grid dim doesn't match, " << headGridSize << " vs " << curGridSize, 1);
+      return 0;
+    }
+#  else
+    assertMsg(headGridSize == curGridSize,
+              "readPdataUni: Grid dim doesn't match, " << headGridSize << " vs " << curGridSize);
+#  endif
+
     // re-allocate all data
     parts->resizeAll(head.dim);
 
@@ -325,6 +338,19 @@ template<class T> int readPdataUni(const std::string &name, ParticleDataImpl<T>
     pdata->getParticleSys()->resize(head.dim);  // ensure that parent particle system has same size
     pdata->resize(head.dim);
 
+    const Vec3i curGridSize = pdata->getParent()->getGridSize();
+    const Vec3i headGridSize(head.dimX, head.dimY, head.dimZ);
+#  if BLENDER
+    // Correct grid size is only a soft requirement in Blender
+    if (headGridSize != curGridSize) {
+      debMsg("readPdataUni: Grid dim doesn't match, " << headGridSize << " vs " << curGridSize, 1);
+      return 0;
+    }
+#  else
+    assertMsg(headGridSize == curGridSize,
+              "readPdataUni: Grid dim doesn't match, " << headGridSize << " vs " << curGridSize);
+#  endif
+
     assertMsg(head.dim == pdata->size(), "pdata size doesn't match");
 #  if FLOATINGPOINT_PRECISION != 1
     ParticleDataImpl<T> temp(pdata->getParent());
diff --git a/extern/mantaflow/preprocessed/fileio/ioutil.cpp b/extern/mantaflow/preprocessed/fileio/ioutil.cpp
index 2c7ac7be00e..2bac34c2a65 100644
--- a/extern/mantaflow/preprocessed/fileio/ioutil.cpp
+++ b/extern/mantaflow/preprocessed/fileio/ioutil.cpp
@@ -90,6 +90,13 @@ template<> void convertFrom(openvdb::Vec3s &in, Vec3 *out)
   (*out).z = in.z();
 }
 
+template<> void convertFrom(openvdb::Vec3i &in, Vec3i *out)
+{
+  (*out).x = in.x();
+  (*out).y = in.y();
+  (*out).z = in.z();
+}
+
 // Convert to OpenVDB value from Manta value.
 template<class S, class T> void convertTo(S *out, T &in)
 {
diff --git a/extern/mantaflow/preprocessed/fileio/iovdb.cpp b/extern/mantaflow/preprocessed/fileio/iovdb.cpp
index 3641577beca..cc2d0aa508d 100644
--- a/extern/mantaflow/preprocessed/fileio/iovdb.cpp
+++ b/extern/mantaflow/preprocessed/fileio/iovdb.cpp
@@ -38,6 +38,11 @@
 #define POSITION_NAME "P"
 #define FLAG_NAME "U"
 
+#define META_BASE_RES "file_base_resolution"
+#define META_VOXEL_SIZE "file_voxel_size"
+#define META_BBOX_MAX "file_bbox_max"
+#define META_BBOX_MIN "file_bbox_min"
+
 using namespace std;
 
 namespace Manta {
@@ -388,7 +393,8 @@ int writeObjectsVDB(const string &filename,
                     int compression,
                     int precision,
                     float clip,
-                    const Grid<Real> *clipGrid)
+                    const Grid<Real> *clipGrid,
+                    const bool meta)
 {
   openvdb::initialize();
   openvdb::io::File file(filename);
@@ -489,6 +495,16 @@ int writeObjectsVDB(const string &filename,
     // Set additional grid attributes, e.g. name, grid class, compression level, etc.
     if (vdbGrid) {
       setGridOptions<openvdb::GridBase>(vdbGrid, objectName, gClass, voxelSize, precision);
+
+      // Optional metadata: Save additional simulation information per vdb object
+      if (meta) {
+        const Vec3i size = object->getParent()->getGridSize();
+        // The (dense) resolution of this grid
+        vdbGrid->insertMeta(META_BASE_RES,
+                            openvdb::Vec3IMetadata(openvdb::Vec3i(size.x, size.y, size.z)));
+        // Length of one voxel side
+        vdbGrid->insertMeta(META_VOXEL_SIZE, openvdb::FloatMetadata(voxelSize));
+      }
     }
   }
 
@@ -533,6 +549,44 @@ int writeObjectsVDB(const string &filename,
   return 1;
 }
 
+static void clearAll(std::vector<PbClass *> *objects, std::vector<ParticleDataBase *> pdbBuffer)
+{
+  // Clear all data loaded into manta objects (e.g. during IO error)
+  for (std::vector<PbClass *>::iterator iter = objects->begin(); iter != objects->end(); ++iter) {
+    if (GridBase *mantaGrid = dynamic_cast<GridBase *>(*iter)) {
+      if (mantaGrid->getType() & GridBase::TypeInt) {
+        Grid<int> *mantaIntGrid = (Grid<int> *)mantaGrid;
+        mantaIntGrid->clear();
+      }
+      else if (mantaGrid->getType() & GridBase::TypeReal) {
+        Grid<Real> *mantaRealGrid = (Grid<Real> *)mantaGrid;
+        mantaRealGrid->clear();
+      }
+      else if (mantaGrid->getType() & GridBase::TypeVec3) {
+        Grid<Vec3> *mantaVec3Grid = (Grid<Vec3> *)mantaGrid;
+        mantaVec3Grid->clear();
+      }
+    }
+    else if (BasicParticleSystem *mantaPP = dynamic_cast<BasicParticleSystem *>(*iter)) {
+      mantaPP->clear();
+    }
+  }
+  for (ParticleDataBase *pdb : pdbBuffer) {
+    if (pdb->getType() == ParticleDataBase::TypeInt) {
+      ParticleDataImpl<int> *mantaPDataInt = (ParticleDataImpl<int> *)pdb;
+      mantaPDataInt->clear();
+    }
+    else if (pdb->getType() == ParticleDataBase::TypeReal) {
+      ParticleDataImpl<Real> *mantaPDataReal = (ParticleDataImpl<Real> *)pdb;
+      mantaPDataReal->clear();
+    }
+    else if (pdb->getType() == ParticleDataBase::TypeVec3) {
+      ParticleDataImpl<Vec3> *mantaPDataVec3 = (ParticleDataImpl<Vec3> *)pdb;
+      mantaPDataVec3->clear();
+    }
+  }
+}
+
 int readObjectsVDB(const string &filename, std::vector<PbClass *> *objects, float worldSize)
 {
 
@@ -561,6 +615,9 @@ int readObjectsVDB(const string &filename, std::vector<PbClass *> *objects, floa
   // A buffer to store a handle to pData objects. These will be read alongside a particle system.
   std::vector<ParticleDataBase *> pdbBuffer;
 
+  // Count how many objects could not be read correctly
+  int readFailure = 0;
+
   for (std::vector<PbClass *>::iterator iter = objects->begin(); iter != objects->end(); ++iter) {
 
     if (gridsVDB.empty()) {
@@ -568,11 +625,12 @@ int readObjectsVDB(const string &filename, std::vector<PbClass *> *objects, floa
     }
     // If there is just one grid in this file, load it regardless of name match (to vdb caches per
     // grid).
-    bool onlyGrid = (gridsVDB.size() == 1);
+    const bool onlyGrid = (gridsVDB.size() == 1);
 
     PbClass *object = dynamic_cast<PbClass *>(*iter);
     const Real dx = object->getParent()->getDx();
-    const Real voxelSize = worldSize * dx;
+    const Vec3i origRes = object->getParent()->getGridSize();
+    Real voxelSize = worldSize * dx;
 
     // Particle data objects are treated separately - buffered and inserted when reading the
     // particle system
@@ -596,6 +654,81 @@ int readObjectsVDB(const string &filename, std::vector<PbClass *> *objects, floa
       if (!nameMatch && !onlyGrid) {
         continue;
       }
+
+      // Metadata: If present in the file, meta data will be parsed into these fields
+      Real metaVoxelSize(0);
+      Vec3i metaRes(0), metaBBoxMax(0), metaBBoxMin(0);
+
+      // Loop to load all meta data that we care about
+      for (openvdb::MetaMap::MetaIterator iter = vdbGrid->beginMeta(); iter != vdbGrid->endMeta();
+           ++iter) {
+        const std::string &name = iter->first;
+        const openvdb::Metadata::Ptr value = iter->second;
+        if (name.compare(META_BASE_RES) == 0) {
+          openvdb::Vec3i tmp = static_cast<openvdb::Vec3IMetadata &>(*value).value();
+          convertFrom(tmp, &metaRes);
+        }
+        else if (name.compare(META_VOXEL_SIZE) == 0) {
+          float tmp = static_cast<openvdb::FloatMetadata &>(*value).value();
+          convertFrom(tmp, &metaVoxelSize);
+
+          voxelSize = metaVoxelSize;  // Make sure to update voxel size variable (used in
+                                      // pointgrid's importVDB())
+          if (worldSize != 1.0)
+            debMsg(
+                "readObjectsVDB: Found voxel size in meta data. worldSize parameter will be "
+                "ignored!",
+                1);
+        }
+        else if (name.compare(META_BBOX_MAX) == 0) {
+          openvdb::Vec3i tmp = static_cast<openvdb::Vec3IMetadata &>(*value).value();
+          convertFrom(tmp, &metaBBoxMax);
+        }
+        else if (name.compare(META_BBOX_MIN) == 0) {
+          openvdb::Vec3i tmp = static_cast<openvdb::Vec3IMetadata &>(*value).value();
+          convertFrom(tmp, &metaBBoxMin);
+        }
+        else {
+          debMsg("readObjectsVDB: Skipping unknown meta information '" << name << "'", 1);
+        }
+      }
+
+      // Compare metadata with allocated grid setup. This prevents invalid index access.
+      if (notZero(metaRes) && metaRes != origRes) {
+        debMsg("readObjectsVDB Warning: Grid '" << vdbGrid->getName()
+                                                << "' has not been read. Meta grid res " << metaRes
+                                                << " vs " << origRes << " current grid size",
+               1);
+        readFailure++;
+        break;
+      }
+      if (notZero(metaVoxelSize) && metaVoxelSize != voxelSize) {
+        debMsg("readObjectsVDB Warning: Grid '"
+                   << vdbGrid->getName() << "' has not been read. Meta voxel size "
+                   << metaVoxelSize << " vs " << voxelSize << " current voxel size",
+               1);
+        readFailure++;
+        break;
+      }
+      if (metaBBoxMax.x > origRes.x || metaBBoxMax.y > origRes.y || metaBBoxMax.z > origRes.z) {
+        debMsg("readObjectsVDB Warning: Grid '"
+                   << vdbGrid->getName() << "' has not been read. Vdb bbox max " << metaBBoxMax
+                   << " vs " << origRes << " current grid size",
+               1);
+        readFailure++;
+        break;
+      }
+      const Vec3i origOrigin(0);
+      if (metaBBoxMin.x < origOrigin.x || metaBBoxMin.y < origOrigin.y ||
+          metaBBoxMin.z < origOrigin.z) {
+        debMsg("readObjectsVDB Warning: Grid '"
+                   << vdbGrid->getName() << "' has not been read. Vdb bbox min " << metaBBoxMin
+                   << " vs " << origOrigin << " current grid origin",
+               1);
+        readFailure++;
+        break;
+      }
+
       if (GridBase *mantaGrid = dynamic_cast<GridBase *>(*iter)) {
 
         if (mantaGrid->getType() & GridBase::TypeInt) {
@@ -655,6 +788,17 @@ int readObjectsVDB(const string &filename, std::vector<PbClass *> *objects, floa
         return 0;
       }
     }
+    // Do not continue loading objects in this loop if there was a read error
+    if (readFailure > 0) {
+      break;
+    }
+  }
+
+  if (readFailure > 0) {
+    // Clear all data that has already been loaded into simulation objects
+    clearAll(objects, pdbBuffer);
+    pdbBuffer.clear();
+    return 0;
   }
 
   // Give out a warning if pData items were present but could not be read due to missing particle
@@ -729,7 +873,8 @@ int writeObjectsVDB(const string &filename,
                     int compression,
                     int precision,
                     float clip,
-                    const Grid<Real> *clipGrid)
+                    const Grid<Real> *clipGrid,
+                    const bool meta)
 {
   errMsg("Cannot save to .vdb file. Mantaflow has not been built with OpenVDB support.");
   return 0;
diff --git a/extern/mantaflow/preprocessed/fileio/mantaio.cpp b/extern/mantaflow/preprocessed/fileio/mantaio.cpp
index fe29890ec11..ff57ab532e6 100644
--- a/extern/mantaflow/preprocessed/fileio/mantaio.cpp
+++ b/extern/mantaflow/preprocessed/fileio/mantaio.cpp
@@ -85,7 +85,8 @@ int save(const string &name,
          bool precisionHalf = true,
          int precision = PRECISION_HALF,
          float clip = 1e-4,
-         const Grid<Real> *clipGrid = nullptr)
+         const Grid<Real> *clipGrid = nullptr,
+         const bool meta = false)
 {
 
   if (!precisionHalf) {
@@ -105,7 +106,7 @@ int save(const string &name,
     return writeGridsVol(name, &objects);
   if (ext == ".vdb")
     return writeObjectsVDB(
-        name, &objects, worldSize, skipDeletedParts, compression, precision, clip, clipGrid);
+        name, &objects, worldSize, skipDeletedParts, compression, precision, clip, clipGrid, meta);
   else if (ext == ".npz")
     return writeGridsNumpy(name, &objects);
   else if (ext == ".txt")
@@ -134,6 +135,7 @@ static PyObject *_W_1(PyObject *_self, PyObject *_linargs, PyObject *_kwds)
       int precision = _args.getOpt<int>("precision", 6, PRECISION_HALF, &_lock);
       float clip = _args.getOpt<float>("clip", 7, 1e-4, &_lock);
       const Grid<Real> *clipGrid = _args.getPtrOpt<Grid<Real>>("clipGrid", 8, nullptr, &_lock);
+      const bool meta = _args.getOpt<bool>("meta", 9, false, &_lock);
       _retval = toPy(save(name,
                           objects,
                           worldSize,
@@ -142,7 +144,8 @@ static PyObject *_W_1(PyObject *_self, PyObject *_linargs, PyObject *_kwds)
                           precisionHalf,
                           precision,
                           clip,
-                          clipGrid));
+                          clipGrid,
+                          meta));
       _args.check();
     }
     pbFinalizePlugin(parent, "save", !noTiming);
diff --git a/extern/mantaflow/preprocessed/fileio/mantaio.h b/extern/mantaflow/preprocessed/fileio/mantaio.h
index 088d43556e1..26e9319e5e9 100644
--- a/extern/mantaflow/preprocessed/fileio/mantaio.h
+++ b/extern/mantaflow/preprocessed/fileio/mantaio.h
@@ -77,7 +77,8 @@ int writeObjectsVDB(const std::string &filename,
                     int compression = COMPRESSION_ZIP,
                     int precision = PRECISION_HALF,
                     float clip = 1e-4,
-                    const Grid<Real> *clipGrid = nullptr);
+                    const Grid<Real> *clipGrid = nullptr,
+                    const bool meta = false);
 int readObjectsVDB(const std::string &filename,
                    std::vector<PbClass *> *objects,
                    float scale = 1.0);
diff --git a/extern/mantaflow/preprocessed/gitinfo.h b/extern/mantaflow/preprocessed/gitinfo.h
index afc34a00d3d..ddc644db724 100644
--- a/extern/mantaflow/preprocessed/gitinfo.h
+++ b/extern/mantaflow/preprocessed/gitinfo.h
@@ -1,3 +1,3 @@
 
 
-#define MANTA_GIT_VERSION "commit e2285cb9bc492987f728123be6cfc1fe11fe73d6"
+#define MANTA_GIT_VERSION "commit 1c86d86496e7f7473c36248d12ef07bf4d9d2840"
diff --git a/extern/mantaflow/preprocessed/grid.cpp b/extern/mantaflow/preprocessed/grid.cpp
index 61672129f37..e0ea3830fae 100644
--- a/extern/mantaflow/preprocessed/grid.cpp
+++ b/extern/mantaflow/preprocessed/grid.cpp
@@ -508,8 +508,7 @@ struct CompMaxVec : public KernelBase {
 
 template<class T> Grid<T> &Grid<T>::copyFrom(const Grid<T> &a, bool copyType)
 {
-  assertMsg(a.mSize.x == mSize.x && a.mSize.y == mSize.y && a.mSize.z == mSize.z,
-            "different grid resolutions " << a.mSize << " vs " << this->mSize);
+  assertMsg(a.mSize == mSize, "different grid resolutions " << a.mSize << " vs " << this->mSize);
   memcpy(mData, a.mData, sizeof(T) * mSize.x * mSize.y * mSize.z);
   if (copyType)
     mType = a.mType;  // copy type marker
@@ -3402,8 +3401,7 @@ void PbRegister_markIsolatedFluidCell()
 void copyMACData(
     const MACGrid &source, MACGrid &target, const FlagGrid &flags, const int flag, const int bnd)
 {
-  assertMsg(source.getSize().x == target.getSize().x && source.getSize().y == target.getSize().y &&
-                source.getSize().z == target.getSize().z,
+  assertMsg(source.getSize() == target.getSize(),
             "different grid resolutions " << source.getSize() << " vs " << target.getSize());
 
   // Grid<Real> divGrid(target.getParent());
diff --git a/extern/mantaflow/preprocessed/grid.h b/extern/mantaflow/preprocessed/grid.h
index cf942a19e9a..3d6f8558b8f 100644
--- a/extern/mantaflow/preprocessed/grid.h
+++ b/extern/mantaflow/preprocessed/grid.h
@@ -596,6 +596,7 @@ template<class T> class Grid : public GridBase {
   //! set data
   inline void set(int i, int j, int k, T &val)
   {
+    DEBUG_ONLY(checkIndex(i, j, k));
     mData[index(i, j, k)] = val;
   }
 
diff --git a/extern/mantaflow/preprocessed/grid4d.cpp b/extern/mantaflow/preprocessed/grid4d.cpp
index 1a79a835854..72bd3a6fe50 100644
--- a/extern/mantaflow/preprocessed/grid4d.cpp
+++ b/extern/mantaflow/preprocessed/grid4d.cpp
@@ -491,9 +491,7 @@ template<class T> Grid4d<T> &Grid4d<T>::safeDivide(const Grid4d<T> &a)
 }
 template<class T> Grid4d<T> &Grid4d<T>::copyFrom(const Grid4d<T> &a, bool copyType)
 {
-  assertMsg(a.mSize.x == mSize.x && a.mSize.y == mSize.y && a.mSize.z == mSize.z &&
-                a.mSize.t == mSize.t,
-            "different Grid4d resolutions " << a.mSize << " vs " << this->mSize);
+  assertMsg(a.mSize == mSize, "different Grid4d resolutions " << a.mSize << " vs " << this->mSize);
   memcpy(mData, a.mData, sizeof(T) * mSize.x * mSize.y * mSize.z * mSize.t);
   if (copyType)
     mType = a.mType;  // copy type marker
diff --git a/intern/mantaflow/intern/MANTA_main.cpp b/intern/mantaflow/intern/MANTA_main.cpp
index 1ed2b558938..6c8e45ceeb4 100644
--- a/intern/mantaflow/intern/MANTA_main.cpp
+++ b/intern/mantaflow/intern/MANTA_main.cpp
@@ -1984,7 +1984,9 @@ float MANTA::getTimestep()
 bool MANTA::needsRealloc(FluidModifierData *fmd)
 {
   FluidDomainSettings *fds = fmd->domain;
-  return (fds->res[0] != mResX || fds->res[1] != mResY || fds->res[2] != mResZ);
+  return ((fds->res_max[0] - fds->res_min[0]) != mResX ||
+          (fds->res_max[1] - fds->res_min[1]) != mResY ||
+          (fds->res_max[2] - fds->res_min[2]) != mResZ);
 }
 
 void MANTA::adaptTimestep()
diff --git a/intern/mantaflow/intern/strings/fluid_script.h b/intern/mantaflow/intern/strings/fluid_script.h
index e65310c4bfd..3bf8e66c110 100644
--- a/intern/mantaflow/intern/strings/fluid_script.h
+++ b/intern/mantaflow/intern/strings/fluid_script.h
@@ -711,7 +711,7 @@ def fluid_file_export_s$ID$(framenr, file_format, path, dict, file_name=None, mo
             file = os.path.join(path, file_name + '_' + framenr + file_format)\n\
             if not os.path.isfile(file) or mode_override:\n\
                 if file_format == '.vdb':\n\
-                    saveCombined = save(name=file, objects=list(dict.values()), worldSize=domainSize_s$ID$, skipDeletedParts=True, compression=vdbCompression_s$ID$, precision=vdbPrecision_s$ID$, clip=vdbClip_s$ID$, clipGrid=clipGrid)\n\
+                    saveCombined = save(name=file, objects=list(dict.values()), worldSize=domainSize_s$ID$, skipDeletedParts=True, compression=vdbCompression_s$ID$, precision=vdbPrecision_s$ID$, clip=vdbClip_s$ID$, clipGrid=clipGrid, meta=True)\n\
                 elif file_format == '.bobj.gz' or file_format == '.obj':\n\
                     for name, object in dict.items():\n\
                         if not os.path.isfile(file) or mode_override:\n\
diff --git a/source/blender/blenkernel/intern/fluid.c b/source/blender/blenkernel/intern/fluid.c
index 0f8a11a40b2..59248e5f9f8 100644
--- a/source/blender/blenkernel/intern/fluid.c
+++ b/source/blender/blenkernel/intern/fluid.c
@@ -4001,8 +4001,11 @@ static void BKE_fluid_modifier_processDomain(FluidModifierData *fmd,
         has_config = manta_read_config(fds->fluid, fmd, mesh_frame);
       }
 
-      /* Update mesh data from file is faster than via Python (manta_read_mesh()). */
-      has_mesh = manta_read_mesh(fds->fluid, fmd, mesh_frame);
+      /* Only load the mesh at the resolution it ways originally simulated at.
+       * The mesh files don't have a header, i.e. the don't store the grid resolution. */
+      if (!manta_needs_realloc(fds->fluid, fmd)) {
+        has_mesh = manta_read_mesh(fds->fluid, fmd, mesh_frame);
+      }
     }
 
     /* Read particles cache. */