I've never worked at a game developer that used a seperate file for the alpha, it's alway a 32-bit tga. But I wouldn't be surprised if there's a company somewhere that does. It just doesn't seem very effecient for the artist or the engine. For prerendered stuff, I use layered psd files and have the bump, spec, diffuse, and…
Thats what I do for pre-rendered work yes. I dont embed the alpha. I paint the transparency map as its own black and white tga. For game engine stuff I suspect that for the most part you would want to embed the alpha ( assuming your engine supports 32 bit targas ) . However, I put areas of a character that use alpha ( e.g…
It depends on what version of Maya you're using. In 4.5 the alpha's should show up automatically if they're in a 32-bit TGA. In 5.0 (and above, I think) you have to connect your texture to the transparency channel. Just drag/drop and you should be set to go. Transparency sorting has improved a bit in the later version...…