为什么没有显示我的对象？

Question

这是我使用幻想艺术制作的3D模型：

我按照本教程为所有感兴趣的人制作了沙漏：

• http://www.artofillusion.org/docs/hourglasstut/index

我将其导出到名为hourglass.obj的文件中。 现在，这是我用来尝试显示对象的代码：

public class LoadAnObject extends Applet
{
    public LoadAnObject()
    {
        setLayout(new BorderLayout());
        GraphicsConfiguration config = SimpleUniverse.getPreferredConfiguration();
        Canvas3D canvas = new Canvas3D(config);
        add("Center", canvas);

        BranchGroup content = getScene();
        content.compile();

        SimpleUniverse universe = new SimpleUniverse(canvas);
        universe.getViewingPlatform().setNominalViewingTransform();
        universe.addBranchGraph(content);
    }

    public BranchGroup getScene()
    {
        BranchGroup group = new BranchGroup();

        ObjectFile object = new ObjectFile();
        Scene scene = null;

        try
        {
            scene = object.load("/Users/John/ArtOfIllusion/Hourglass.obj");
        }catch(Exception e){e.printStackTrace();}

        group.addChild(scene.getSceneGroup());
        return group;
    }

    public static void main(String args[])
    {
        Frame frame = new MainFrame(new LoadAnObject(), 256, 256);
    }
}

无论是编译还是运行它，都没有任何错误，加载时我只会得到一个空白的Universe。 我从这里得到了这段代码：

• http://java.sun.com/developer/onlineTraining/java3d/j3d_tutorial_ch3.pdf （请参阅第3页）

为什么我的对象没有显示在宇宙中？

Answer 1

该对象正在显示，但由于没有光源而无法看到，这是我为使沙漏可见而必须添加的代码：

public BranchGroup getScene()
{
    BranchGroup group = new BranchGroup();

    ObjectFile object = new ObjectFile();
    Scene scene = null;

    try
    {
        scene = object.load("/Users/John/ArtOfIllusion/Hourglass.obj");
    }catch(Exception e){e.printStackTrace();}

    group.addChild(scene.getSceneGroup());

    Color3f light1Color = new Color3f(1.0f, 1.0f, 1.0f);
    BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
    Vector3f light1Direction = new Vector3f(.3f, 0, 0);
    DirectionalLight light1 = new DirectionalLight(light1Color, light1Direction);
    light1.setInfluencingBounds(bounds);
    group.addChild(light1);

    return group;
}