diff --git a/engine/physics/src/model.rs b/engine/physics/src/model.rs
index 2c4aece..25b0f24 100644
--- a/engine/physics/src/model.rs
+++ b/engine/physics/src/model.rs
@@ -314,6 +314,9 @@ impl TryFrom<&model::Mesh> for PhysicsMesh{
 			return Err(PhysicsMeshError::ZeroVertices);
 		}
 		let verts=mesh.unique_pos.iter().copied().map(Vert).collect();
+		// TODO: do not hash faces to get face id
+		// meshes can have multiple identical nd representations while still being distinct faces,
+		// especially when the complete mesh is a non-convex mesh.
 		//TODO: fix submeshes
 		//flat map mesh.physics_groups[$1].groups.polys()[$2] as face_id
 		//lower face_id points to upper face_id