diff --git a/src/model_physics.rs b/src/model_physics.rs
index 6c1cbbb..25ed516 100644
--- a/src/model_physics.rs
+++ b/src/model_physics.rs
@@ -964,12 +964,13 @@ fn is_empty_volume(normals:Vec<Vector3<Fixed<3,96>>>)->bool{
 	for i in 0..len-1{
 		for j in i+1..len{
 			let n=normals[i].cross(normals[j]);
-			let mut d_comp:Option<Fixed<9,{96*3}>>=None;
+			let mut d_comp=None;
 			for k in 0..len{
 				if k!=i&&k!=j{
-					let d=n.dot(normals[k]);
+					let d=n.dot(normals[k]).is_negative();
 					if let Some(comp)=&d_comp{
-						if comp.is_negative()^d.is_negative(){
+						// This is testing if d_comp*d < 0
+						if comp^d{
 							return true;
 						}
 					}else{