My understanding is that ambient light is FAKED (in the absence of Radiosity calculations) by adding a uniform light level everywhere. But this is unrealistic.

In the real world, ambient light (just like ambient audio noise) is caused by direct light being reflected around the environment (becoming "indirect light" = "ambient light"). One of the main purposes of the Radiosity method is to accurately simulate the ambient light in the scene that is missed by other methods (e.g. ray-tracing, etc.). Radiosity does this by dealing with light as power, instead of as rays. So, with Radiosity, there is no need to add a uniform light level to scenes to fake the ambient light level.

Since the indirectly reflected light power calculated by Radiosity IS ambient light, more ambient light level = more Radiosity effect. In other words, what we call "ambient light" is just the sum total of all secondary, and higher order, reflections of light in the scene. Crank up the ambient and you increase the intensity of the reflections.

Make sense?

_jc
Art Head Start.com
Art training e-book for digital artists and students. Free chapter on lighting.

Message edited on: 01/09/2006 14:03