WPF实现3D翻转的动画效果

<Grid MouseDown="Grid_MouseDown">
    <Viewport3D>
        <Viewport3D.Camera>
            <!-- Position属性指定3D空间中摄像机的位置，LookDirection属性为摄像机方向 -->
            <PerspectiveCamera Position="0 0 500" LookDirection="0 0 -1" />
        </Viewport3D.Camera>
        <Viewport3D.Children>
            <ContainerUIElement3D>
                <Viewport2DVisual3D>
                    <Viewport2DVisual3D.Geometry>
                        <!-- Positions属性表示绘制对象的点集合，TriangleIndices属性表示对象的正反面（WPF通过逆时针环绕表示正面），TextureCoordinates属性表示2D纹理映射到3D对象 -->
                        <!-- 一般通过3D建模工具推导得出 -->
                        <MeshGeometry3D Positions="-200 200 0  -200 -200 0  200 -200 0  200 200 0" TriangleIndices="0 1 2  0 2 3" TextureCoordinates="0 0  0 1  1 1  1 0"/>
                    </Viewport2DVisual3D.Geometry>
                    <Viewport2DVisual3D.Material>
                        <DiffuseMaterial Viewport2DVisual3D.IsVisualHostMaterial="True"/>
                    </Viewport2DVisual3D.Material>
                    <Viewport2DVisual3D.Visual>
                        <!-- 放置正面自定义用户控件 -->
                        <Page:Win1 Width="400" Height="400"/>
                    </Viewport2DVisual3D.Visual>
                </Viewport2DVisual3D>
                <Viewport2DVisual3D>
                    <Viewport2DVisual3D.Geometry>
                        <MeshGeometry3D Positions="200 200 0  200 -200 0  -200 -200 0  -200 200 0" TriangleIndices="0 1 2  0 2 3" TextureCoordinates="0 0  0 1  1 1  1 0"/>
                    </Viewport2DVisual3D.Geometry>
                    <Viewport2DVisual3D.Material>
                        <DiffuseMaterial Viewport2DVisual3D.IsVisualHostMaterial="True"/>
                    </Viewport2DVisual3D.Material>
                    <Viewport2DVisual3D.Visual>
                        <!-- 放置反面自定义用户控件 -->
                        <Page:Win2 Width="400" Height="400"/>
                    </Viewport2DVisual3D.Visual>
                </Viewport2DVisual3D>
                <ContainerUIElement3D.Transform>
                    <RotateTransform3D>
                        <RotateTransform3D.Rotation>
                            <!-- 设置旋转轴为对齐坐标系统的Y轴 -->
                            <AxisAngleRotation3D x:Name="aar" Angle="0" Axis="0 1 0"/>
                        </RotateTransform3D.Rotation>
                    </RotateTransform3D>
                </ContainerUIElement3D.Transform>
            </ContainerUIElement3D>
            <ModelVisual3D>
                <ModelVisual3D.Content>
                    <!-- 设置指定方向传播的平行光线填充场景 -->
                    <DirectionalLight Color="Transparent"/>
                </ModelVisual3D.Content>
            </ModelVisual3D>
        </Viewport3D.Children>
    </Viewport3D>
</Grid>

private void Grid_MouseDown(object sender, MouseButtonEventArgs e)
{
    DoubleAnimation da = new DoubleAnimation();
    da.Duration = new Duration(TimeSpan.FromSeconds(1));
    if (e.ClickCount == 2)
        da.To = 0d;
    else
        da.To = 180d;
    AxisAngleRotation3D aar = Application.Current.MainWindow.FindName("aar") as AxisAngleRotation3D;
    aar.BeginAnimation(AxisAngleRotation3D.AngleProperty, da);  
}