The problem: You render stuff in Maya, using mia_material(_x) - or any other "mental ray" shader - but you find that those pixels containing that shader has no alpha. What gives?
The reality is that Maya has a very peculiar notion of Alpha... because the Maya software renderer actually has true three-colored "transparency", so transparency gets passed around separately in the most... odd... ways ;)
Hence, to get the Maya system to "understand" a standard shader that uses alpha, you need to check this here little checkbox:
Then, life should be more fun again!
/Z
