Sprite render in mental ray as well have you tried, or render out as PS or tiff that should keep a alpha channel.............dave thanks for the reply, Dave. Mental Ray doesn't seem to produce anything at all. From what I have read, sprites can only be hardware rendered. I tried MR with various image formats, none of them worked. I tried hardware rendering in all formats, with no success getting a z-depth image that gives me something other than grey cards. Getting the regular alpha is not the problem...getting the "second alpha" that was mentioned in that link is what I was unable to achieve.