A FDynamicMeshOctree3 is available to dynamically track the triangles of the mesh (however the client is responsible for updating this octree). Based on the Octree, the mesh is partitioned into chunks that are stored in separate RenderBuffers in the FOctreeDynamicMeshSceneProxy. Calling NotifyMeshUpdated() will result in only the "dirty" chunks being updated, rather than the entire mesh.