Layered Textures and Mental Ray
 

1. I create a layered texure with 3 layers.
2. I use 3d paint tool to create 2 black-n-white textures.
3. I assign 1 of the b&w textures to the alpha of the top layer of the layered texture.
4. I assign the other b&w texture to the alpha of the middle layer of the layered texture.
5. I render out in Maya Software, I can see all 3 layers.
6. I render out in Mental Ray, I can only see the top 2 layers.

Other people I know have the same result. Works with Software but not with MR. I've played around with alot of settings and searched Maya Help but I haven't come up with a reason yet. Anybody know why it won't work in MR? I've attached luminence nodes to the b&w textures. I've even set them to "alpha is luminance", etc. The texture sample looks fine, just doesn't render out properly in MR.

what blend mode are you using?

Top Layer=Over
Middle=Over
Bottom=None

it works for me. I must be doing something different.

I'll play around with it again.

why are you using rgb>luminance? have you tried without?

No, but I'll try without. I figured since the b&w doesn't have transparency info that I needed it. I'll try it without, thx.

That did the trick, much thanks. At first it didn't work without the luminance node so I went into the b&w attributes under color balance and turned on "alpha is luminance" and that did the trick. Shouldn't the luminance node do the same thing as turning on "alpha is luminance"? Or is it two different things?