Cutout Opacity

[mad187]

Hey guys,

I am from a mental ray background. What is the V-ray equivalent of cutout opacity? I tried mapping an alpha image to the transparency input of the vraymtl. But due to GI, I get black dots and issues. I'd like to know what the equivalent, i reckon it would make my life easier for zdepth pass and other things too.

Thanks

[vlado]

You can just use the opacity slot of the VRayMtl material. You need the z-depth element to have filtering enabled in order for it to respect opacity.

If you get black dots, it probably means that you have overlapping faces (triangles that occupy exactly the same space). There are ways to deal with that (either through the "backface cull" option of V-Ray, or through the "Secondary rays bias"), but it is best to avoid them.

Best regards,
Vlado

[mad187]

Hey Vlado, Yes I do in fact have a lot overlapping faces. But what is the best way to deal with this for "tree leaves"? Specifically to the tree leave shaders. I can't do the backface cull option I assume as that would mean some of my leaves would disappear. And is there a way to apply the secondary ray bias specifically to this shader? So that the rest of the scene would render as per normal?

Also does this overlapping issue cause very long render times? I am testing some scenes out that involves a forest and all that. So I am trying to solve my production pipeline and figure out v-rays capabilities. From a distance I can't see these issues so I can ignore it as well unless you think it causes rays to calculate forever or something.

On another note, thank you for V-ray. I am really loving it by the day and will probably end up buying it soon. It really feels so much better then MentalRay as I don't see myself clicking 10 thousand buttons. Cheers to chaosgroup