diff --git a/public/robot_kinematics_three_test.html b/public/robot_kinematics_three_test.html
index 661a4bb..be32103 100644
--- a/public/robot_kinematics_three_test.html
+++ b/public/robot_kinematics_three_test.html
@@ -490,6 +490,8 @@
       import { OrbitControls } from "three/addons/controls/OrbitControls.js";
       import SmartWasmAPI from "./wasm/smart_api_wrapper.js";
 
+      THREE.Object3D.DEFAULT_UP.set(0, 0, 1);
+
       const api = new SmartWasmAPI();
       const jointCount = 6;
       const state = {
@@ -530,7 +532,8 @@
       scene.background = new THREE.Color(0xdfe7ec);
 
       const camera = new THREE.PerspectiveCamera(45, 1, 0.01, 80);
-      camera.position.set(1.1, -1.75, 1.05);
+      camera.up.set(0, 0, 1);
+      camera.position.set(1.18, -1.68, 0.92);
 
       const renderer = new THREE.WebGLRenderer({
         canvas: elements.canvas,
@@ -542,7 +545,24 @@
 
       const controls = new OrbitControls(camera, renderer.domElement);
       controls.enableDamping = true;
+      controls.screenSpacePanning = false;
       controls.target.set(0.18, 0, 0.34);
+      controls.update();
+
+      window.__robotKinematicsDebug = {
+        // 获取当前相机状态，用于验证按钮操作不会改变视角。
+        getCameraState() {
+          return {
+            position: camera.position.toArray(),
+            up: camera.up.toArray(),
+            target: controls.target.toArray(),
+          };
+        },
+        // 获取 three.js 默认上方向，用于验证场景为 Z 轴向上。
+        getDefaultUp() {
+          return THREE.Object3D.DEFAULT_UP.toArray();
+        },
+      };
 
       const robotGroup = new THREE.Group();
       const targetGroup = new THREE.Group();
@@ -906,7 +926,6 @@
             .join(", ");
         }
 
-        fitCamera(points);
       }
 
       // 创建两个关节点之间的连杆圆柱。
@@ -930,23 +949,6 @@
         return mesh;
       }
 
-      // 根据当前骨架范围调整相机目标。
-      function fitCamera(points) {
-        if (!points.length) {
-          return;
-        }
-
-        const box = new THREE.Box3().setFromPoints(points);
-        const center = box.getCenter(new THREE.Vector3());
-        const size = box.getSize(new THREE.Vector3()).length();
-        controls.target.copy(center);
-        if (size > 0) {
-          camera.near = 0.01;
-          camera.far = Math.max(20, size * 18);
-          camera.updateProjectionMatrix();
-        }
-      }
-
       // 清空三维分组。
       function clearGroup(group) {
         while (group.children.length > 0) {
@@ -1002,7 +1004,6 @@
           targetMaterial,
         );
         marker.position.fromArray(targetPose.position);
-        marker.rotation.x = Math.PI / 2;
         targetGroup.add(marker);
 
         const axes = new THREE.AxesHelper(0.18);