IPR CUDA : Layered texture 'alpha is luminance' and reflection glossiness broken.

[francomanko]

Hi it seems again that there are problems with the alpha is luminance setting in the layered texture setting. Render with cpu/ipr its fine, with cuda its broken.


1.Create a vraymtl and layered texture.
2. Change colour of first layer to white
3. Connect alpha of layered texture to reflection glossiness.

render in cpu and then cuda

Also if you connect the layered texture to the reflection color and have the colour slider at full (i.e white) it renders black, it seems if you have rgb set to 1,1,1 it wont work either.


This is with vray 3.5 release and maya 2016

[francomanko]

Ok so it looks like its not the alpha is luminance, its just the whole layered texture doesnt work with reflection glossiness, ive tried connecting the rgb channels individually and it doesnt work in cuda mode.

[yolov]

Seems like a bug, I'll let the devs know. Until we fix it, you can try passing the color result from the layered texture through a luminance node and it should work. Will that work for you? Here's an example:

[yolov]

Actually it works for me with "alpha is luminance" enabled, I don't know why it wouldn't in your case. You could share the scene so we can have a look, if that's OK. Other than that, it renders perfectly fine here on the GPU.

[francomanko]

thats a bit odd, as i just created a fresh scene, based on my first post and the error is there. Anyway ive attached project folder and scene.

Thanks

[yolov]

Thanks, I think I know what's going on now. It is a bug, from the looks of it, but here's what you can try as a workaround, until it's fixed: with alpha is luminance the alpha is considered to be 0 by the GPU, when the color is pure white, try a non-pure-white value. Or if you want areas of pure white - lower the layer's alpha and untick "alpha is luminance" - seems to work well too.

[francomanko]

Thanks for reply, but i only used the white color layer as a quick example of it being broken, i would always have textures in there really.

Also can you send me your scene that works with your workaround, because i have the same problem, it works with cpu but not cuda?

thanks

[yolov]

Here's a quick example




layeredTex_GPU.zip
Edit: You'll have to replace the HDR I've used with another one, since I haven't included it.

[francomanko]

Ive loaded the scene as is, rendered an ipr with cuda, and all i get is a grey sphere. Cpu works fine

[yolov]

You are correct, I just realized that it actually doesn't work with the official build. In any case - it's already been reported to the devs and I'll let you know when there's a fix.
But I also tried piping a luminance node between the layeredTex and the vrayMtl and it seems to work with GPU, could you try that?

[francomanko]

yeah that works...thx for help.