Quote - i'd be fine with a mat zone, myself.  that said, does anyone know if something completely transparent still slows down raytraced lights?

That's a good point. Transparency means more work for the renderer, unless it's clever enough to see that the transparent part is actually completely invisible. In certain situations - you know, if someone does renders for foot and forehead fetishist, for example  - it might save a significant amount of time to hide that geometry inside the figure instead.

-- I'm not mad at you, just Westphalian.