Add compound shape for rigid body simulation

This patch adds a new compound shape entry to the shape selection
dropdown. It also corrects wrong inertia calculation for convex hulls,
that resulted in strange behavior for small objects.

The compound shape take the collision shapes from its object children
and combines them. This makes it possible to create concave shapes from
primitive shapes. Using this instead of the mesh collision shape is
often many times faster.

Reviewed By: Sergey, Sebastian Parborg

Differential Revision: http://developer.blender.org/D5797

1 files changed, 10 insertions, 0 deletions

diff --git a/source/blender/depsgraph/intern/builder/deg_builder_relations.cc b/source/blender/depsgraph/intern/builder/deg_builder_relations.cc
index 8932d875776..5ae71dd1792 100644
--- a/source/blender/depsgraph/intern/builder/deg_builder_relations.cc
+++ b/source/blender/depsgraph/intern/builder/deg_builder_relations.cc
@@ -1704,6 +1704,16 @@ void DepsgraphRelationBuilder::build_rigidbody(Scene *scene)
       if (object->rigidbody_object->type == RBO_TYPE_PASSIVE) {
         continue;
       }
+
+      if (object->parent != nullptr && object->parent->rigidbody_object != nullptr &&
+          object->parent->rigidbody_object->shape == RB_SHAPE_COMPOUND) {
+        /* If we are a child of a compound shape object, the transforms and sim evaluation will be
+         * handled by the parent compound shape object. Do not add any evaluation triggers
+         * for the child objects.
+         */
+        continue;
+      }
+
       OperationKey rb_transform_copy_key(
           &object->id, NodeType::TRANSFORM, OperationCode::RIGIDBODY_TRANSFORM_COPY);
       /* Rigid body synchronization depends on the actual simulation. */