What is global illusstration in 3ds max?
I think you are talking about global illumination, which is a
rendering property under both mental ray and vray rendering
engine.
Global illumination is a term used to describe how light
reflects off of diffuse surfaces, such as a wall, and illuminates
other objects. For example, if you were to shine a light at a red
wall in a dark room, the entire room will appear red as light is
bouncing off of the wall. In both mental ray and vray, photons are
used to simulate rays of light bouncing off of objects. You can
google how to videos for rendering with global illumination for
more info.