问如何使用PointGeometryModel3D显示Helix.Toolkit.Wpf.SharpDx

EN

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        DataContext = this;
    }
    public PointGeometry3D Geometry
    {
        get
        {
            var vc = new Vector3Collection();
            var id = new IntCollection();

            vc.Add(new Vector3(0, 0, 0));
            id.Add(0);
            vc.Add(new Vector3(2, 0, 0));
            id.Add(1);
            vc.Add(new Vector3(0, 2, 0));
            id.Add(2);
            vc.Add(new Vector3(0, 0, 2));
            id.Add(3);
            vc.Add(new Vector3(2, 2, 0));
            id.Add(4);
            vc.Add(new Vector3(0, 2, 2));
            id.Add(5);
            vc.Add(new Vector3(2, 0, 2));
            id.Add(6);
            vc.Add(new Vector3(2, 2, 2));
            id.Add(7);

            var g = new PointGeometry3D() { Positions = vc, Indices = id };
            return g;
        }

    }
}

<hx:Viewport3DX>
    <hx:Viewport3DX.Camera>
    <hx:PerspectiveCamera Position="0,0,10" LookDirection="0,0,-1" UpDirection="0,1,0"/>
    </hx:Viewport3DX.Camera>
    <hx:AmbientLight3D/>
    <hx:PointGeometryModel3D Geometry="{Binding Geometry}" Size="2 2" Color="Bisque"/>
</hx:Viewport3DX>