diff --git a/src/graphics.rs b/src/graphics.rs
index 1e82523..340bba2 100644
--- a/src/graphics.rs
+++ b/src/graphics.rs
@@ -250,6 +250,7 @@ impl GraphicsState{
 						});
 						texture_index
 					};
+					//this utm_id is going to take a lot of hashing to generate!
 					unique_texture_models[utm_id.get() as usize].instances.push(instance);
 				}
 			}
diff --git a/src/model_physics.rs b/src/model_physics.rs
index aed4165..a049e34 100644
--- a/src/model_physics.rs
+++ b/src/model_physics.rs
@@ -338,6 +338,7 @@ impl From<&model::Mesh> for PhysicsMesh{
 					for &v in poly_vertices{
 						dot+=normal.dot(mesh.unique_pos[mesh.unique_vertices[v.get() as usize].pos.get() as usize]);
 					}
+					//assume face hash is stable, and there are no flush faces...
 					let face=Face{normal,dot:dot/len as i64};
 					let face_id=match face_id_from_face.get(&face){
 						Some(&face_id)=>face_id,