What's it all about?While some simple rendering algorithms treat the user-defined light sources as the ONLY source of light, so the underside or back side of objects are TOTALLY BLACK, we know that some light rattles around in the space a little and will eventually arrive at the back/under side of a shape. This light is approximated by ambient light a number usually given an intensity level of 5-20% of maximum. This light is simply everywhere, without regard to the placement or orientation of the surface or viewer.
Ambient light onlyThis image illustrates a scene in which there is ONLY ambient light. In this case the light has been set to 50% of maximum.
Notice how all surfaces of the same "color" are actually rendered the same, so surface definition is almost non-existent.
We need a direction-dependent component to the light!
Last updated: April, 2014