From the sounds of things you are looking for a technique called 'baking' where by the render differences is applied straight onto the model's texture, like in these examples;
As far as I know the only two programs that do this is Cinema 4D 7 and above (with the baker plugin which the plugin is free, I think it comes standard with vers. 9)
or the freebie alternative
Blender, blender is perfectly capable of 'baking' in fact the image about was done in Blender, and here is a link to the tutorial;
http://vegastrike.sourceforge.net/wiki/HowTo:Radiosity_baking_in_Blender
I am sparticus and so is my wife