diff --git a/engine/physics/src/model.rs b/engine/physics/src/model.rs
index bddb094d..2cd7291c 100644
--- a/engine/physics/src/model.rs
+++ b/engine/physics/src/model.rs
@@ -68,7 +68,7 @@ pub enum FEV<M:MeshQuery>{
 }
 
 //use Unit32 #[repr(C)] for map files
-#[derive(Clone,Hash,Eq,PartialEq)]
+#[derive(Clone,Copy,Hash,Eq,PartialEq)]
 struct Face{
 	normal:Planar64Vec3,
 	dot:Planar64,
@@ -324,6 +324,8 @@ impl TryFrom<&model::Mesh> for PhysicsMesh{
 		//flat map mesh.physics_groups[$1].groups.polys()[$2] as face_id
 		//lower face_id points to upper face_id
 		//the same face is not allowed to be in multiple polygon groups
+		// because SubmeshFaceId -> CompleteMeshFaceId -> SubmeshFaceId is ambiguous
+		// when multiple SubmeshFaceId point to one MeshFaceId
 		let mut faces=Vec::new();
 		let mut face_id_from_face=HashMap::new();
 		let mesh_topologies:Vec<PhysicsMeshTopology>=mesh.physics_groups.iter().map(|physics_group|{
@@ -387,15 +389,11 @@ impl TryFrom<&model::Mesh> for PhysicsMesh{
 						normal:(normal/len as i64).divide().narrow_1().unwrap(),
 						dot:(dot/(len*len) as i64).narrow_1().unwrap(),
 					};
-					let face_id=match face_id_from_face.get(&face){
-						Some(&face_id)=>face_id,
-						None=>{
-							let face_id=MeshFaceId::new(faces.len() as u32);
-							face_id_from_face.insert(face.clone(),face_id);
-							faces.push(face);
-							face_id
-						}
-					};
+					let face_id=*face_id_from_face.entry(face).or_insert_with(||{
+						let face_id=MeshFaceId::new(faces.len() as u32);
+						faces.push(face);
+						face_id
+					});
 					submesh_faces.push(face_id);
 					face_ref_guys.push(FaceRefEdges(face_edges));
 				}
@@ -403,16 +401,16 @@ impl TryFrom<&model::Mesh> for PhysicsMesh{
 			PhysicsMeshTopology{
 				faces:submesh_faces,
 				verts:submesh_verts,
-				face_topology:face_ref_guys.into_iter().map(|face_ref_guy|{
-					FaceRefs{edges:face_ref_guy.0}
+				face_topology:face_ref_guys.into_iter().map(|FaceRefEdges(edges)|{
+					FaceRefs{edges}
 				}).collect(),
-				edge_topology:edge_pool.edge_guys.into_iter().map(|(edge_ref_verts,edge_ref_faces)|
-					EdgeRefs{faces:edge_ref_faces.0,verts:edge_ref_verts.0}
+				edge_topology:edge_pool.edge_guys.into_iter().map(|(EdgeRefVerts(verts),EdgeRefFaces(faces))|
+					EdgeRefs{faces,verts}
 				).collect(),
-				vert_topology:vert_ref_guys.into_iter().map(|vert_ref_guy|
+				vert_topology:vert_ref_guys.into_iter().map(|VertRefGuy{edges,faces}|
 					VertRefs{
-						edges:vert_ref_guy.edges.into_iter().collect(),
-						faces:vert_ref_guy.faces.into_iter().collect(),
+						edges:edges.into_iter().collect(),
+						faces:faces.into_iter().collect(),
 					}
 				).collect(),
 			}