Use Render Layers to define how single geometries should be rendered and displayed. This feature is only available in Raytracing mode. The procedure described here uses a car and its accompanying geometries as an example.
Double-click inside the columns of the Render Layer dialog box to disable or enable different levels of visibility for the geometry in each layer.
For example, you could turn PrimaryVisibility off for the car, and the geometry of the car will not be visible, but its other effects will be, such as shadows.
Click
(Activate Layer) to see the results of your selections.