In reply to Tony's question: can I compare SLA plastic to Brian's plastic when they aren't the same?

True, the SLA and final materials are different, but it's the best comparison I have right now. Best case scenario is: the polycarbonate in the final part will allow light to flood the walls so they don't look like a darker outline, thus filling the entire button face with light. Worst case scenario is: the polycarbonate will fiercely block the light, leaving only the inner triangle of light.

Either way, it seems like you get more light with the hollow buttons. If it's the worst case and only the inner triangle lights up, it's still a bigger area of light than the filled buttons, who's light appears only the size of the LEDs themselves.

The knob is also in question; filled or hollow. I don't have an SLA MKIIa knob to preview (yet) so I can't compare. My hunch is that the light is dampened by passing through all that plastic. If the light filled the big hollow space and hit the thin walls, it may look really full.

My bottom line hunch about filled buttons is "The light illuminates the inside face of the button (the surface nearest the light). We see that lit face through a centimeter of plastic, which makes it dimmer." Look at your lit filled buttons from the side with the player on in the dark. You'll see the face of the button doesn't really seem lit. Yet, as you slowly turn the player 90 degrees to face you head on, you'll see the lit inside face come into alignment with the clear outside face, thus showing you the light. This is most notable with the top button; from where I sit in my car, the top button almost seems dark because I can't see the inside face. ::sigh:: It's hard to describe. The point is, on the hollow buttons, the outside face is lit directly instead of through a centimeter of plastic.

I'll keep trying to find a way to prototype these in the final material, but I'm sure it won't happen at a cost the project can afford. I just need to get it right the first time because modifications will be expensive.