The Shadow CatcherThe Shadow Catcher can be used to create shadows cast by objects onto the surrounding background imagery. The shadows cast are not limited to simply a ground plane but can be cast onto other surfaces of varying shapes. material capture shadows. It becomes visible in areas that are in shadows, while other areas become transparent to the render (figure 1).
Figure 1: The Shadow Catcher material applied to a surface plane.
Enabled - The material is transparent unless there is some direct shadow cast onto the material, which makes it less transparent depending on the shadow strength.
Opacity - Controls the transparency of the shadows via a greyscale information.