improve serialization based on feedback: make it easier to serialize a single object, or single shape, or single bvh. Modified Bullet/Demos/ConcaveDemo to use btSerializer to serialize the btOptimizedBvh (or optionally the trimesh+bvh) You can also serialize trimesh without BVH, use: serializer->setSerializationFlags(BT_SERIALIZE_NO_BVH);// or BT_SERIALIZE_NO_TRIANGLEINFOMAP