how do i get the value of light/energy hitting an object? so i can use that value to drive colors :)

Attached Link: Shoe String Shaders

I don't know, but shoe string shaders has some plugins that edge on that so that may offer assistance. Lit is the tool in the plugin I am referencing. For that matter Mark or Eric may be of help. Did you get the sdk from carrara or sign up for the sdk list? Can just download it now. Might help for some of the stuff you are doing.

No need to think outside the box....
    Just make it invisible.