VRay Two Sided Overview
The VRay Two Sided material is a utility material provided with the V-Ray renderer. The material allows seeing the light on the backside of the objects. Use this material to simulate thin translucent surfaces like paper, cloth curtains, tree leaves etc.
VRay Two Sided Parameters
Front material - this is the material which will be used for front-side faces as defined by the object normals.
Back material - this is the material V-Ray will be used for back side faces as defined by their normals.
Color- this determines which side (front or back) relative to the camera is more visible in the rendering process. By default this color is black (0.0), which means that only the front side will be visible. When this color is closer to white (1.0) the more of the back material is going to be seen. When it is closer to black (0.0), the more of the material facing the camera is going be seen..
Force One-Sided - when is is on (the default), the sub-materials will render as one-sided materials. Turning this option off is not recommended.