oooh that's kinda cool! In 3dsmax you have an AO shader which u can apply to any channel on your material you want (though it'll obviously not be usefull everywhere), but i dont think it's got a gradient control assigned... Though probably that could be bypassed by introducing a falloff or gradient shader to one or both of the color channels of the AO shader... I'll have to run a test with that some time.

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