rotation handles now include motor range indicators

script.js

@@ -8,7 +8,7 @@ const renderer = new THREE.WebGLRenderer({ canvas, antialias: true });
 renderer.setSize(window.innerWidth, window.innerHeight);
 
 const scene = new THREE.Scene();
-scene.background = new THREE.Color(0x111111);
+scene.background = new THREE.Color(0xaaaaaa);
 
 const camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 100);
 camera.position.set(2, 2, 2);
@@ -18,7 +18,9 @@ camera.lookAt(0, 0, 0);
 scene.add(new THREE.AmbientLight(0xffffff, 0.6));
 const directional = new THREE.DirectionalLight(0xffffff, 0.8);
 directional.position.set(15, 10, 7);
-scene.add(directional);
+const directional2 = new THREE.DirectionalLight(0xffffff, 0.8);
+directional2.position.set(-15, 10, -7);
+scene.add(directional2);
 
 // Controls
 const controls = new OrbitControls(camera, renderer.domElement);
@@ -81,39 +83,63 @@ function createRotationArc(axis, lower, upper, radius = 0.1, segments = 32) {
 }
 
 function createRotationSector(axis, lower, upper, radius = 0.1, segments = 64) {
-    const shape = new THREE.Shape();
-    shape.moveTo(0, 0);
+    const motorMargin = 0.4; // hardcoded extra range beyond joint limits
+    const motorLower = lower - motorMargin;
+    const motorUpper = upper + motorMargin;
 
-    for (let i = 0; i <= segments; i++) {
-        const angle = lower + (upper - lower) * (i / segments);
-        shape.lineTo(Math.cos(angle) * radius, Math.sin(angle) * radius);
-    }
-
-    shape.lineTo(0, 0); // close the shape
-
-    const geometry = new THREE.ShapeGeometry(shape);
-    const material = new THREE.MeshBasicMaterial({
-        color: 0x888888,         // light gray
+    const redMaterial = new THREE.MeshBasicMaterial({
+        color: 0xff0000,
         transparent: true,
-        opacity: 0.3,            // translucent
-        side: THREE.DoubleSide,  // show both sides of the fill
-        depthTest: false,        // ✅ always on top
+        opacity: 0.2,
+        side: THREE.DoubleSide,
+        depthTest: false,
         depthWrite: false
     });
 
+    const whiteMaterial = new THREE.MeshBasicMaterial({
+        color: 0xffffff,
+        transparent: true,
+        opacity: 0.6,
+        side: THREE.DoubleSide,
+        depthTest: false,
+        depthWrite: false
+    });
 
-    const mesh = new THREE.Mesh(geometry, material);
+    function createArc(start, end, material) {
+        const shape = new THREE.Shape();
+        shape.moveTo(0, 0);
+        for (let i = 0; i <= segments; i++) {
+            const angle = start + (end - start) * (i / segments);
+            shape.lineTo(Math.cos(angle) * radius, Math.sin(angle) * radius);
+        }
+        shape.lineTo(0, 0);
+        const geometry = new THREE.ShapeGeometry(shape);
+        return new THREE.Mesh(geometry, material);
+    }
 
-    // Orient the sector to match the axis
+    const redLeft = createArc(motorLower, lower, redMaterial);
+    const whiteArc = createArc(lower, upper, whiteMaterial);
+    const redRight = createArc(upper, motorUpper, redMaterial);
+
+    // Orient all arcs to match the axis
     const basis = new THREE.Matrix4();
     const up = new THREE.Vector3(0, 0, 1);
     const quaternion = new THREE.Quaternion().setFromUnitVectors(up, axis.clone().normalize());
     basis.makeRotationFromQuaternion(quaternion);
-    mesh.applyMatrix4(basis);
 
-    return mesh;
+    redLeft.applyMatrix4(basis);
+    whiteArc.applyMatrix4(basis);
+    redRight.applyMatrix4(basis);
+
+    const group = new THREE.Group();
+    group.add(redLeft);
+    group.add(whiteArc);
+    group.add(redRight);
+
+    return group;
 }
 
+
 function createAngleIndicator(axis, angle, radius = 0.1) {
     const dir = new THREE.Vector3(Math.cos(angle), Math.sin(angle), 0).multiplyScalar(radius);
 
@@ -127,7 +153,7 @@ function createAngleIndicator(axis, angle, radius = 0.1) {
         linewidth: 2,            // note: linewidth only works in some renderers
         depthTest: false,        // ✅ always on top
         depthWrite: false
-});
+    });
 
     const line = new THREE.Line(geometry, material);