VRay for SketchUp Manual
Light and Shadow
The quality of Shadow
Unless the shadow is turned off, all objects will cast shadow under light.
The quality of shadow is controlled by Subdivs under lighting dialog box.
Rectangular light for example, under Sampling>Subdivs, please change the default
8 accordingly to get desire shadow quality. The higher number will cost more
time to render. When set it to 32, you can get the almost perfect shadow without
Image on the left is rendered with Subdivs set to 8; image on the right is
set to 32.
Radius for Shadow
When using Point lights, the shadow edge will be very sharp. To improve it,
adjust the Radius under Shadow dialog box. Using Point Light here for example,
image on the left is rendered with Radius set to 0. Image on the right is
rendered with Radius increased to 10.
The Shadow Color
In order to change the shadow color, click the color picker under the shadow