diff --git a/src/Common/InterfereUtil.ts b/src/Common/InterfereUtil.ts
index 033908dbe..caecab564 100644
--- a/src/Common/InterfereUtil.ts
+++ b/src/Common/InterfereUtil.ts
@@ -146,6 +146,9 @@ export class CheckInterfereTool
                     let [b1, b2] = [t1 === 1 ? <ExtrudeSolid>e1.Clone() : (<ExtrudeHole>e1).Convert2ExtrudeSolid(),
                     t2 === 1 ? <ExtrudeSolid>e2.Clone() : (<ExtrudeHole>e2).Convert2ExtrudeSolid()];
 
+                    b1.ClearDraw();
+                    b2.ClearDraw();
+
                     if (!b1.Subtract([b2], []) && !b1.IsErase
                         && !b2.Subtract([b1], []) && !b2.IsErase)
                         continue;