The project provides single attached property that allow different elements to clip the other one (usually a border).
Let's assume we have two borders and a star (path) placed on them. We want the star to clip those borders nicely. This is how it can be done.
<Grid Grid.Row="1">
<Grid clipping:ClippingExtension.ClippingDistance="20">
<clipping:ClippingExtension.ClippingElements>
<clipping:ClippingElementContainer Element="{Binding ElementName=StarControl}"/>
</clipping:ClippingExtension.ClippingElements>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition Width="40"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Border CornerRadius="20" BorderBrush="Black" BorderThickness="5" Background="LightBlue"/>
<Border CornerRadius="20" BorderBrush="Black" BorderThickness="5" Background="LightBlue" Grid.Column="2"/>
</Grid>
<ContentControl x:Name="StarControl" Content="{StaticResource Star}" VerticalAlignment="Stretch"/>
</Grid>
But it will obvously be much easier to check the sample project.