diff --git a/resources/views/rd/fire-shutter-drawing/index.blade.php b/resources/views/rd/fire-shutter-drawing/index.blade.php
index 692ec1c0..9f126863 100644
--- a/resources/views/rd/fire-shutter-drawing/index.blade.php
+++ b/resources/views/rd/fire-shutter-drawing/index.blade.php
@@ -1143,19 +1143,38 @@ function fs3dBuild() {
         const motorBkThick = motorBkD; // 18mm
         const motorBkCX = motorDir * (W1 / 2 - motorBkThick / 2);
         const motorR = b.shaftDia * 0.45;
-        const motorSprocketR = 130 * 0.35; // shaftSprocketR * 0.35
-        const motorZ = -(130 + motorSprocketR + 20); // 모터 Z 오프셋 (-Z = 셔터박스 뒤쪽)
+        const shaftSprocketR = 70; // 브라켓 높이(180mm) 내 크기 (ø140)
+        const motorSprocketR = 30; // 모터측 작은 스프로켓 (ø60)
+        const motorZ = -(shaftSprocketR + motorSprocketR + 20); // 모터 Z 오프셋 (-Z = 셔터박스 뒤쪽)
         // 브라켓: Z 중심은 샤프트(0)와 모터(motorZ) 사이
         const motorBkGeo = new THREE.BoxGeometry(motorBkThick, motorBkH, motorBkW);
         const motorBk = new THREE.Mesh(motorBkGeo, bracketMat);
         motorBk.position.set(motorBkCX, 0, motorZ / 2);
         meshes.motor.add(motorBk);
 
-        // --- 2) 스프로켓 위치 기준 (체인 경로 계산용, 메시 없음) ---
-        const shaftSprocketR = 130;
+        // --- 2) 스프로켓 톱니바퀴 (샤프트측 + 모터측) ---
         const sprocketThick = 12;
         const sprocketFaceX = motorDir * (W1 / 2 - motorBkThick);
         const shaftSprocketX = sprocketFaceX - motorDir * sprocketThick / 2;
+        const sprocketMat = new THREE.MeshStandardMaterial({ color: 0x374151, metalness: 0.6, roughness: 0.35 });
+
+        // 샤프트 스프로켓 톱니바퀴
+        const shaftSpGroup = new THREE.Group();
+        const shaftSpBodyGeo = new THREE.CylinderGeometry(shaftSprocketR * 0.85, shaftSprocketR * 0.85, sprocketThick, 32);
+        shaftSpBodyGeo.rotateZ(Math.PI / 2);
+        shaftSpGroup.add(new THREE.Mesh(shaftSpBodyGeo, sprocketMat));
+        const shaftTeethCount = 18;
+        const toothH = 8, toothTW = 6;
+        for (let i = 0; i < shaftTeethCount; i++) {
+            const a = (i / shaftTeethCount) * Math.PI * 2;
+            const tGeo = new THREE.BoxGeometry(sprocketThick * 0.8, toothTW, toothH);
+            const t = new THREE.Mesh(tGeo, sprocketMat);
+            t.position.set(0, (shaftSprocketR - toothH / 2) * Math.sin(a), (shaftSprocketR - toothH / 2) * Math.cos(a));
+            t.rotation.x = a;
+            shaftSpGroup.add(t);
+        }
+        shaftSpGroup.position.set(shaftSprocketX, 0, 0);
+        meshes.motor.add(shaftSpGroup);
 
         // --- 3) 모터 (샤프트와 수평방향 Z 오프셋 — 슬랫과 간섭 없음) ---
         const motorBodyLen = motorR * 3;
@@ -1190,12 +1209,23 @@ function fs3dBuild() {
         mMount.position.set(motorCX, -motorR - 2.5, motorZ);
         meshes.motor.add(mMount);
 
-        // 모터 출력 스프로켓 (샤프트 스프로켓과 같은 X면, Z=motorZ)
-        const mSpGeo = new THREE.CylinderGeometry(motorSprocketR, motorSprocketR, sprocketThick, 20);
-        mSpGeo.rotateZ(Math.PI / 2);
-        const mSpMesh = new THREE.Mesh(mSpGeo, darkMat);
-        mSpMesh.position.set(shaftSprocketX, 0, motorZ);
-        meshes.motor.add(mSpMesh);
+        // 모터 출력 스프로켓 톱니바퀴 (샤프트 스프로켓과 같은 X면, Z=motorZ)
+        const mSpGroup = new THREE.Group();
+        const mSpBodyGeo = new THREE.CylinderGeometry(motorSprocketR * 0.8, motorSprocketR * 0.8, sprocketThick, 20);
+        mSpBodyGeo.rotateZ(Math.PI / 2);
+        mSpGroup.add(new THREE.Mesh(mSpBodyGeo, sprocketMat));
+        const motorTeethCount = 10;
+        const mToothH = 6, mToothTW = 5;
+        for (let i = 0; i < motorTeethCount; i++) {
+            const a = (i / motorTeethCount) * Math.PI * 2;
+            const tGeo = new THREE.BoxGeometry(sprocketThick * 0.8, mToothTW, mToothH);
+            const t = new THREE.Mesh(tGeo, sprocketMat);
+            t.position.set(0, (motorSprocketR - mToothH / 2) * Math.sin(a), (motorSprocketR - mToothH / 2) * Math.cos(a));
+            t.rotation.x = a;
+            mSpGroup.add(t);
+        }
+        mSpGroup.position.set(shaftSprocketX, 0, motorZ);
+        meshes.motor.add(mSpGroup);
 
         // --- 4) 체인 (RS #40, YZ 평면 — 수평으로 두 스프로켓 연결) ---
         // 샤프트 스프로켓: (Y=0, Z=0), 모터 스프로켓: (Y=0, Z=motorZ)
@@ -1222,18 +1252,21 @@ function fs3dBuild() {
         chainLine.position.x = shaftSprocketX;
         meshes.motor.add(chainLine);
 
-        // 체인 직선 두께 (상/하단)
+        // 체인 직선 두께 (상/하단 — 스프로켓 반지름 차이만큼 기울기 적용)
         const tangentLen = Math.sqrt(Math.pow(R1 - R2, 2) + motorZ * motorZ);
         if (tangentLen > 10) {
             const halfZ = motorZ / 2;
+            const chainTilt = Math.atan2(R1 - R2, Math.abs(motorZ)); // 반지름 차이에 의한 기울기
             // 상단 직선
             const csGeo = new THREE.BoxGeometry(6, 4, tangentLen);
             const csTop = new THREE.Mesh(csGeo, chainMat);
             csTop.position.set(shaftSprocketX, (R1 + R2) / 2, halfZ);
+            csTop.rotation.x = chainTilt;
             meshes.motor.add(csTop);
             // 하단 직선
             const csBot = new THREE.Mesh(csGeo.clone(), chainMat);
             csBot.position.set(shaftSprocketX, -(R1 + R2) / 2, halfZ);
+            csBot.rotation.x = -chainTilt;
             meshes.motor.add(csBot);
         }