diff --git a/web/app/brep/operations/boolean.js b/web/app/brep/operations/boolean.js
index 9fbc87ca..b8ef0ee0 100644
--- a/web/app/brep/operations/boolean.js
+++ b/web/app/brep/operations/boolean.js
@@ -149,7 +149,7 @@ function detectLoops(face) {
       if (!candidates) {
         break;
       }
-      edge = findMaxTurningLeft(edge, candidates, edge.loop.face.surface.normal);
+      edge = findMaxTurningLeft(edge, candidates, face.surface.normal);
       if (seen.has(edge)) {
         break;
       }