3 files changed, 13 insertions, 0 deletions
diff --git a/intern/cycles/blender/blender_mesh.cpp b/intern/cycles/blender/blender_mesh.cpp
index 940a923e5af..f6c7319e210 100644
--- a/intern/cycles/blender/blender_mesh.cpp
+++ b/intern/cycles/blender/blender_mesh.cpp
@@ -539,6 +539,12 @@ void BlenderSync::sync_mesh_motion(BL::Object b_ob, Mesh *mesh, int motion)
 	if(!size || !ccl::BKE_object_is_deform_modified(b_ob, b_scene, preview))
 		return;
 
+	/* ensure we only sync instanced meshes once */
+	if(mesh_motion_synced.find(mesh) != mesh_motion_synced.end())
+		return;
+
+	mesh_motion_synced.insert(mesh);
+
 	/* get derived mesh */
 	BL::Mesh b_mesh = object_to_mesh(b_data, b_ob, b_scene, true, !preview, false);
 
diff --git a/intern/cycles/blender/blender_object.cpp b/intern/cycles/blender/blender_object.cpp
index 461e897efe1..ba584e172dc 100644
--- a/intern/cycles/blender/blender_object.cpp
+++ b/intern/cycles/blender/blender_object.cpp
@@ -405,6 +405,9 @@ void BlenderSync::sync_objects(BL::SpaceView3D b_v3d, int motion)
 		mesh_synced.clear();
 		particle_system_map.pre_sync();
 	}
+	else {
+		mesh_motion_synced.clear();
+	}
 
 	/* object loop */
 	BL::Scene::objects_iterator b_ob;
@@ -492,6 +495,9 @@ void BlenderSync::sync_objects(BL::SpaceView3D b_v3d, int motion)
 			scene->particle_system_manager->tag_update(scene);
 		mesh_synced.clear();
 	}
+
+	if(motion)
+		mesh_motion_synced.clear();
 }
 
 void BlenderSync::sync_motion(BL::SpaceView3D b_v3d, BL::Object b_override)
diff --git a/intern/cycles/blender/blender_sync.h b/intern/cycles/blender/blender_sync.h
index f6e19229578..295b1fcee5c 100644
--- a/intern/cycles/blender/blender_sync.h
+++ b/intern/cycles/blender/blender_sync.h
@@ -108,6 +108,7 @@ private:
 	id_map<ObjectKey, Light> light_map;
 	id_map<ParticleSystemKey, ParticleSystem> particle_system_map;
 	set<Mesh*> mesh_synced;
+	set<Mesh*> mesh_motion_synced;
 	void *world_map;
 	bool world_recalc;