Opacity maps aren't working?

[rita_sobral]

Hi Alexander.Atanasov there are more issues than just that with the current workaround.

One issue with the refraction workaround for opacity maps is that it can produce artifacts, likely due to the amount of bounces Vantage does with refractions... For example, a model from Character Creator, the characters hair uses opacity maps, as you move around the character in the scene it can produce black patches across the hair blades and that will change depending on the viewing angle this is with IOR set to 1 on refraction

And another one is that it doesn't play well with overlapping meshes. Again on a character model coming out of Character Creator you need an opacity map on the scalp to blend in with the head and with the current workaround it produces an unwanted glare and an outline of the mesh that you otherwise would not get with a proper opacity map.

Another one is when used in conjunction with scattering fog and let's say you have a large plane that you are adding a fog/cloud sprite too. Currently scattering fog has an issue when you turn on Affecting Secondary Rays which I've gone into detail on another post here https://forums.chaos.com/forum/chaos...-or-refraction

Personally, I think having the option to switch between clip and full mode in Vantage would be the easiest change/addition. That way if you are in control of whether you take the small performance hit for the sake of rendering things as they should be rendered...

Thanks

[Alexander.Atanasov]

Hi vasile_bulgac1,

Can you check again to see if it works now?
https://drive.google.com/file/d/1J-B...ew?usp=sharing

Hi rita_sobral,

Again on a character model coming out of Character Creator you need an opacity map on the scalp to blend in with the head and with the current workaround it produces an unwanted glare and an outline of the mesh.

Can you please share a screenshot and material setup with that issue?

Best regards,
Alexander

[vladimir.nedev]

One issue with the refraction workaround for opacity maps is that it can produce artifacts, likely due to the amount of bounces Vantage does with refractions... For example, a model from Character Creator, the characters hair uses opacity maps, as you move around the character in the scene it can produce black patches across the hair blades and that will change depending on the viewing angle this is with IOR set to 1 on refraction

The "full" opacity mode when implemented will have the same limitation in terms of number of bounces as refraction.
The "clip" opacity can be implemented at a lower level where ray/triangle intersections are being determined, but the same cannot happen with the "full" opacity.
Of course, we can have a separate "max opacity depth" parameter, but this will likely have an even bigger performance impact.

That way if you are in control of whether you take the small performance hit for the sake of rendering things as they should be rendered...

It's not a given that switching to "full" opacity will have a "small" performance hit.
Especially if you have trees/vegetation in your scene that require only "clip" opacity, but their V-Ray material is not setup properly and they actually use "full" opacity.

Greetings,
Vladimir Nedev

[npg]

"Full" would probably look worse in interactive mode when moving (Optix denoiser) or when using DLSS, because of increased noise. That's what the option would be useful for, of course.

[rita_sobral]

Here are some screenshots of the issue with the scalp on a character from Character Creator. I tried the same shader setup on vray gpu, and vray gpu does not have the issue that Vantage does with the same shader? I think it has something to do with reflections, maybe reflection bounces? Not sure...

Both of these are using the opacity map inverted in the refraction with IOR set to 1. If I disable reflections in Vantage using the global setting then you cannot see the outline.

Also included a couple of hair examples.

I can work around the above issues for now but the one I can't work around is the scattering fog issue as the Affect Secondary Rays option is not working as it should when compared to Vray GPU.

Thanks
Tom

[vladimir.nedev]

Can you send us the scene with this character (with materials and textures) ?

Greetings,
Vladimir Nedev

[rita_sobral]

Yes, I'll send it over later today to your email. Thanks

[vasile_bulgac1]

Hi vasile_bulgac1,

Can you check again to see if it works now?
https://drive.google.com/file/d/1J-B...ew?usp=sharing

Hi rita_sobral,

Can you please share a screenshot and material setup with that issue?

Best regards,
Alexander

It's working