diff --git a/resources/views/rd/fire-shutter-drawing/index.blade.php b/resources/views/rd/fire-shutter-drawing/index.blade.php
index e9d728fd..692ec1c0 100644
--- a/resources/views/rd/fire-shutter-drawing/index.blade.php
+++ b/resources/views/rd/fire-shutter-drawing/index.blade.php
@@ -1151,22 +1151,11 @@ function fs3dBuild() {
         motorBk.position.set(motorBkCX, 0, motorZ / 2);
         meshes.motor.add(motorBk);
 
-        // --- 2) 샤프트 스프로켓 (ø260, 브라켓 안쪽) ---
+        // --- 2) 스프로켓 위치 기준 (체인 경로 계산용, 메시 없음) ---
         const shaftSprocketR = 130;
         const sprocketThick = 12;
         const sprocketFaceX = motorDir * (W1 / 2 - motorBkThick);
         const shaftSprocketX = sprocketFaceX - motorDir * sprocketThick / 2;
-        const sSpGeo = new THREE.CylinderGeometry(shaftSprocketR, shaftSprocketR, sprocketThick, 36);
-        sSpGeo.rotateZ(Math.PI / 2);
-        const sSpMesh = new THREE.Mesh(sSpGeo, darkMat);
-        sSpMesh.position.set(shaftSprocketX, 0, 0);
-        meshes.motor.add(sSpMesh);
-        // 스프로켓 허브
-        const hubGeo = new THREE.CylinderGeometry(b.shaftDia * 0.7, b.shaftDia * 0.7, sprocketThick + 6, 16);
-        hubGeo.rotateZ(Math.PI / 2);
-        const hub = new THREE.Mesh(hubGeo, metalMat);
-        hub.position.set(shaftSprocketX, 0, 0);
-        meshes.motor.add(hub);
 
         // --- 3) 모터 (샤프트와 수평방향 Z 오프셋 — 슬랫과 간섭 없음) ---
         const motorBodyLen = motorR * 3;