diff --git a/src/model_physics.rs b/src/model_physics.rs
index b387264..f11f634 100644
--- a/src/model_physics.rs
+++ b/src/model_physics.rs
@@ -472,11 +472,9 @@ impl MeshQuery<MinkowskiFace,MinkowskiDirectedEdge,MinkowskiVert> for MinkowskiM
 	fn edge_faces(&self,edge_id:MinkowskiEdge)->Cow<[MinkowskiFace;2]>{
 		match edge_id{
 			MinkowskiEdge::VertEdge(v0,e1)=>{
-				//tracking index with an external variable because .enumerate() is not available
-				let mut i=0;
-				Cow::Owned(self.mesh1.edge_faces(e1).map(|edge_face_id1|{
-					let face_parity=i==0;
-					i+=1;
+				//faces are listed backwards from the minkowski mesh
+				let e1f=self.mesh1.edge_faces(e1);
+				Cow::Owned([(e1f[1],true),(e1f[0],false)].map(|(edge_face_id1,face_parity)|{
 					let mut best_edge=None;
 					let mut best_d=Planar64::ZERO;
 					let edge_face1_n=self.mesh1.face_nd(edge_face_id1).0;
@@ -495,6 +493,7 @@ impl MeshQuery<MinkowskiFace,MinkowskiDirectedEdge,MinkowskiVert> for MinkowskiM
 				}))
 			},
 			MinkowskiEdge::EdgeVert(e0,v1)=>{
+				//tracking index with an external variable because .enumerate() is not available
 				let mut i=0;
 				Cow::Owned(self.mesh0.edge_faces(e0).map(|edge_face_id0|{
 					let face_parity=i==0;