Skydome alpha...

[evanerichards]

Quick question.
I am rendering a scene with a skydome. However, I don't want the skydome to contribute alpha as that pretty much blocks out the entire scenes alpha. Is there a way to have the skydomes alpha not contribute to the overall scene? I tried to use a vray wrapper but that didn't seem to work.
Any ideas?

Thanks!

[stezza]

turn on invisible in it's attributes!

[evanerichards]

Well I want the sky to show (I am using an HDR image as a texture map). So turning it invisible will just...turn off the sky. I want the sky to show, but not contribute an alpha.

[pechart]

That's the default in mental ray, right? But why do you want to show the sky? Because if you comp it after rendering you will be happy, that the premult is against a black background. Or just for reference in the viewport?
And if you turn the sky invisible, it will keep emitting light and being visible in reflections and stuff.

[evanerichards]

I don't know anything about mental ray. That's why I'm using vray.
Yes. Its true I could add the sky in comp. But I don't want to. I want to have it in the render and skip having to render a second pass and skip having to comp it. As far as I can tell there is not any reason to have an alpha on a skydome. Why would you ever want to? A skydome that covers your entire scene effectively makes the alpha for everything white. Why would I want a completely white alpha? It makes no sense.

I know I can get it in the comp but that's not what I'm asking. Is there a way to turn off the skydome alpha. It seems like you should be able to especially since you can turn it off in 3ds max. I'm just wanting to be sure there isn't something I'm missing.

[pechart]

Ok, just checked it and you can get this effect, if you turn the light invisible, override your environment and plug the texture of the light into the background slot. Only thing is, you have to put a multiply node between your file texture and the background texture slot to match the multiplier in the domelight, if used.

EDIT: Ups, seems that the multiply kicks out the alpha again. Have to check again. Maybe just raise the intensity with the color gain in the file texture for now.

[evanerichards]

Nice! Thank you. I hadn't thought about that approach. Its strange that 3ds max just has a toggle switch to turn the alpha off but maya does not. Weird.

Thanks again!!!

[pechart]

No problem, glad to help.

[stezza]

Vlado ! If you listening in, could we have this switch for maya?