Egret3D中创建球体模型的功能由`SphereGeometry`类实现，通过`SphereGeometry`你可以创建一个默认半径为100，分段数均为50的球体。

下面示例我们创建一个半径为50，同时分段数均为10的球体，代码如下：

```
class SphereDemo extends LoadingUI {
    /**
     * Canvas操作对象
     * @version Egret 3.0
     * @platform Web,Native
     */
    protected _egret3DCanvas: egret3d.Egret3DCanvas;
    /**
    * View3D操作对象
    * @version Egret 3.0
    * @platform Web,Native
    */
    protected _view3D: egret3d.View3D;
    /**
    * look at 摄像机控制器 。</p>
    * 指定摄像机看向的目标对象。</p>
    * 1.按下鼠标左键并移动鼠标可以使摄像机绕着目标进行旋转。</p>
    * 2.按下键盘的(w s a d) 可以摄像机(上 下 左 右)移动。</p>
    * 3.滑动鼠标滚轮可以控制摄像机的视距。</p>
    * @version Egret 3.0
    * @platform Web,Native
    */
    private cameraCtl: egret3d.LookAtController;
    /**
    * 灯光组
    * @version Egret 3.0
    * @platform Web,Native
    */
    private lights: egret3d.LightGroup = new egret3d.LightGroup();
    /**
    * 模型对象
    * @version Egret 3.0
    * @platform Web,Native
    */
    private model: egret3d.Mesh;
    /**
    * 待机动画
    * @version Egret 3.0
    * @platform Web,Native
    */
    private idle: egret3d.SkeletonAnimationClip;
    /**
    * 跑步动画
    * @version Egret 3.0
    * @platform Web,Native
    */
    private run: egret3d.SkeletonAnimationClip;
    /**
    * 攻击动画
    * @version Egret 3.0
    * @platform Web,Native
    */
    private attack: egret3d.SkeletonAnimationClip;
    /**
     * @language zh_CN
     * 当前动画
     */
    public currentAnim: string;


    public constructor() {
        

        super();

        ///创建Canvas对象。
        this._egret3DCanvas = new egret3d.Egret3DCanvas();
        ///Canvas的起始坐标，页面左上角为起始坐标(0,0)。
        this._egret3DCanvas.x = 0;
        this._egret3DCanvas.y = 0;
        ///设置Canvas页面尺寸。
        this._egret3DCanvas.width = window.innerWidth;
        this._egret3DCanvas.height = window.innerHeight;
        ///创建View3D对象,页面左上角为起始坐标(0,0),其参数依次为:
        ///@param x: number 起始坐标x,
        ///@param y: number 起始坐标y
        ///@param  width: number 显示区域的宽
        ///@param  height: number 显示区域的高
        this._view3D = new egret3d.View3D(0,0,window.innerWidth,window.innerHeight);
        ///当前对象对视位置,其参数依次为:
        ///@param pos 对象的位置
        ///@param target 目标的位置
        this._view3D.camera3D.lookAt(new egret3d.Vector3D(0,0,1000),new egret3d.Vector3D(0,0,0));
        ///View3D的背景色设置
        this._view3D.backColor = 0xffffffff;
        ///将View3D添加进Canvas中
        this._egret3DCanvas.addView3D(this._view3D);

        ///创建平行光
        var dirLight: egret3d.DirectLight = new egret3d.DirectLight(new egret3d.Vector3D(-0.5,0.6,0.2));
        dirLight.diffuse = 0xffffff;
        this.lights.addLight(dirLight);

        this.InitCameraCtl();

        ///启动Canvas。
        this._egret3DCanvas.start();
        this._egret3DCanvas.addEventListener(egret3d.Event3D.ENTER_FRAME,this.update,this);

        this.OnInitLoadingView(5);


        ///设置window resize事件
        egret3d.Input.addEventListener(egret3d.Event3D.RESIZE,this.OnWindowResize,this);
        
        this.createCube();
    }

    /**
    * @language zh_CN        
    * 窗口尺寸变化事件
    * @version Egret 3.0
    * @platform Web,Native
    */
    private OnWindowResize(e: egret3d.Event3D): void {
        ///重置ui大小
        this._egret3DCanvas.width = window.innerWidth;
        this._egret3DCanvas.height = window.innerHeight;
        this._view3D.width = window.innerWidth;
        this._view3D.height = window.innerHeight;
    }

    /**
    * @language zh_CN        
    * 初始化相机控制
    * @version Egret 3.0
    * @platform Web,Native
    */
    private InitCameraCtl() {
        ///摄像机控制类
        this.cameraCtl = new egret3d.LookAtController(this._view3D.camera3D,new egret3d.Object3D());
        ///设置目标和相机的距离
        this.cameraCtl.distance = 500;
        ///设置相机x轴旋转
        this.cameraCtl.rotationX = 0;
    }

    /**
    * @language zh_CN        
    * 模型加载回调
    * @param e: egret3d.URLLoader 加载器对象
    * @version Egret 3.0
    * @platform Web,Native
    */
    protected createCube() {
        this.OnLoadFinished();
        this.CloseLoadingView();

        ///创建纹理材质
        var mat = new egret3d.TextureMaterial();
        ///创建模型基类
        var ge: egret3d.SphereGeometry = new egret3d.SphereGeometry(50,10,10);
        ///生成mesh
        this.model = new egret3d.Mesh(ge,mat);
        this.model.material.lightGroup = this.lights;
        this.model.y = -100;
        ///插入model
        this._view3D.addChild3D(this.model);

    }


    public update(e: egret3d.Event3D) {
        this.cameraCtl.update();
    }
}     
```

编译并运行，效果如图：

![](575cd398500cd.png)