Simple 3D Pie Chart in WPF

<Window x:Class="_3DPie.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="390" Width="450">
    <Grid>
        <DockPanel Width="Auto" VerticalAlignment="Stretch" Height="Auto" HorizontalAlignment="Stretch" Grid.ColumnSpan="1" Grid.Column="0" Grid.Row="0" 
                Margin="0,0,0,0" Grid.RowSpan="1">
            <Viewport3D Name="mainViewport" ClipToBounds="True">
                <Viewport3D.Camera>
                    <OrthographicCamera x:Name="camera" FarPlaneDistance="100" LookDirection="0,10,-10" UpDirection="0,1,0"
                    NearPlaneDistance="-20" Width="100" Position="0,-10,10"/>
                </Viewport3D.Camera>
                <ModelVisual3D>
                    <ModelVisual3D.Content>
                        <DirectionalLight Color="White" Direction="-1,-1,-10"/>
                    </ModelVisual3D.Content>
                </ModelVisual3D>
            </Viewport3D>
        </DockPanel>
    </Grid>
</Window>