(VRaySun and the automatically generated
VRaySky env map for VRay,
or mrSun and mrSky for MentalRay)
2. You enable indirect illumination in VRay,
or FinalGather in MentalRay.
3. Create a standard camera for MentalRay,
or a VRayPhysicalCamera for VRay.
4. For MentalRay go to Rendering > Environment...
menu and make the changes as shown below
For VRay go to the camera's Modify tab
and make the following changes
then open render settings and change the following :
and you are done!