diff --git a/resources/views/rd/fire-shutter-drawing/index.blade.php b/resources/views/rd/fire-shutter-drawing/index.blade.php
index 6aed77f2..0dce13f7 100644
--- a/resources/views/rd/fire-shutter-drawing/index.blade.php
+++ b/resources/views/rd/fire-shutter-drawing/index.blade.php
@@ -980,10 +980,9 @@ function fs3dBuild() {
         meshes.case.position.set(0, H + b.height / 2, 0);
         scene.add(meshes.case);
 
-        // Box wireframe
+        // Box wireframe (child of case — position (0,0,0) relative to parent)
         const boxEdges = new THREE.EdgesGeometry(boxGeo);
         const boxLine = new THREE.LineSegments(boxEdges, new THREE.LineBasicMaterial({ color: 0x94a3b8 }));
-        boxLine.position.copy(meshes.case.position);
         meshes.case.add(boxLine);
 
         // === SHAFT ===