Light select - split off SSS and refraction from the 'specular' elements

[glacierise]

Hi guys,

We're experimenting with our comp people in the process of designing a new CG comp workflow, and the prospect of building the comp 'from the lighs' is enticing. In the current arrangement though, SSS and refraction are part of the 'specular' (bad name?) elements, could these be split off into their dedicated elements? Otherways we can't control these components individually.

Thanks!

[joconnell]

+1 that's the way we work too, no doubt it's coming down the line!

[glacierise]

Also, if you guys give us a way to have a matte for all the rays reflected/refracted etc from an object, that would be great

[vlado]

We're experimenting with our comp people in the process of designing a new CG comp workflow, and the prospect of building the comp 'from the lighs' is enticing. In the current arrangement though, SSS and refraction are part of the 'specular' elements, could these be split off into their dedicated elements?

So you want in addition to direct_diffuse and direct_specular to have direct_sss? And same for indirect? We can do it now, will make a note about it.

Also, if you guys give us a way to have a matte for all the rays reflected/refracted etc from an object, that would be great.

There is already an option to make an object matte to reflections/refractions, doesn't it work for you (see attachment)? Or you mean something else?

Best regards,
Vlado

[glacierise]

There is already an option to make an object matte to reflections/refractions, doesn't it work for you (see attachment)? Or you mean something else?

I rather meant giving us a mask that selects all contributions of an object, rather just the camera rays that we get from Cryptomatte. So that we could color correct all the contribution of the object, and not leave its reflection unaffected. Is that possible?

So you want in addition to direct_diffuse and direct_specular to have direct_sss? And same for indirect? We can do it now, will make a note about it.

Yes, and refraction too, thanks!

[joconnell]

Just the alpha component to go along with the rgb parts effectively? Even though you'd ignore it when comping!

[glacierise]

Just the alpha component to go along with the rgb parts effectively? Even though you'd ignore it when comping!

Not really - I'll put together an example so it's easier to explain. But that's another topic

[joconnell]

Oh I understand now! That'd be a very handy global one alright, I think it's in there with full LPE's by default?

[kosso_olli]

And the prospect of building the comp 'from the lighs' is enticing.

Could you please explain what this means exactly? I am always curious to try new things out, maybe this could be interesting for us as well. What are the benefits?

[joconnell]

At the minute, the vray reflection element for example contains the reflection / specular from everything in the scene. If you turned down a light in the shot, it's bounce light, spec, reflect and refract should also go down with it, but that's hard to do with an all in pass. Say for example you've got a really exact render that you're happy with but want a bit of flexibility afterwards, you could skip all of the usual passes and instead put out a light select for each light or group of lights in complete mode (which should include literally all contribution from that light) and then do simple mix up and downs to tweak your comp. In the version hristo is talking about, you can get the various different sub parts of each light contribution also - you'll end up with more passes since rather than one VrayGI pass for example, you'll end up with Gi x number of lights you want a pass for. Say you decide a light is twice as strong as you want it though, you can have a master grade after you've combined all of it's direct/gi/spec/ref/refract/sss and then dial down everything correctly to keep your natural results.

[jasonhuang1115]

Thank you John. I am curious if Chaos is interested in putting some of that tweak-ability in VFB as part of the upcoming light mixer where we can tweak light's intensity in VFB (a bit like 3delight) during IPR.

[glacierise]

Thanks for helping out with the explanation John - Jason, I'll post the Nuke script and the test render tomorrow so there can be a real example out here and we can give it a thought.

[glacierise]

Here's a Nuke file with some comp options and a test render. Files at https://drive.google.com/drive/folde...0U?usp=sharing