pre-made comp of passes.

[super gnu]

i was wondering if there is any automated solution to creating a fully layered comp from vray?

i.e. using all the necessary passes to recreate the beauty pass, with all the blending modes set?


i looked at psd manager, but as far as i can tell, it wont actually layer up a comp correctly for you, as you have to set the blending modes and layer orders(plus choose relevant passes) yourself.


on a related note, is there an accepted 100% reliable method (and guide) for recreating the beauty pass from individual passes? i always end up just using the rgb (beauty pass) and tweaking using masks.. i rearely use the actual reflection/gi/diffuse/lighting passes even if i render them out.. mainly because ive never found the way to get a comp that looks exactly like the rgb pass.

[3LP]

Are you using PS or AFX (or something else?)

If you use PS, then I don't know, if you use AFX, I have a comp somewhere that's 2 years old and use the much talked about way to comp exactly 1:1 pixel perfect reconstructed layered comp. It's fairly heavy to use though as it uses un-premultiplication and re-premultiplications to have perfect aliasing.
Because it's all automated, you only need to point your path and it will create everything automatically.
Something similar can fairly quickly be done in nuke or fusion I guess.

AFAIK not in PS as there are lot of things that PS doesn't support and that comping soft does.

Stan

[super gnu]

thanks for the reply. i use PS and Afx. but currently im doing more still work, so i was initially thinking of a way to spit out a pre-made comp psd (i was hoping this is what psd manager did)


having said that (in cs6 at least) 32 bit doesn't even allow all the blending modes, so i guess youd be stuck at 16 bit in any case.

[3LP]

Yes but the main issue with PS is that it doesn't even support pre-multiply by black, who is the base of comping soft.
So there already, you're stuck :/

Stan

[Rens]

on a related note, is there an accepted 100% reliable method (and guide) for recreating the beauty pass from individual passes? i always end up just using the rgb (beauty pass) and tweaking using masks.. i rearely use the actual reflection/gi/diffuse/lighting passes even if i render them out.. mainly because ive never found the way to get a comp that looks exactly like the rgb pass.

Here's the math and general setup, probably more than you need as I wrote this up with Nuke in mind and it's a full explanation. : )


Simple setup:
BeautyRGB = reflection + refraction + lighting + GI + specular + selfIllum + SSS(*)
Note that in PS this needs to be ADD, not screen.


Now to get a bit deeper you can adjust the raw render elements. The idea is to split up the passes, tweak them, merge them back together and then add them up to get the beauty.

baseDiffuse(*) = diffuse(Filter) / inverted reflectionFilter
rawReflection = reflection / reflectionFilter
rawRefraction = refraction / refractionFilter
rawLighting = lighting / diffuse
rawGI = GI / diffuse
rawSpecular(*) = specular / reflectionFilter
lighting without shadows = lighting + shadows

I like to adjust material properties separately from environment properties. I haven't seen this done anywhere else but to me it makes the most sense as it mirrors the 3D workflow and is likely more intuitive.
For material properties (the colour of the object, refl amount, etc.) adjust
baseDiffuse,
reflectionFilter,
refractionFilter.

For environment properties (the colour of the light hitting the object) adjust
rawReflection,
rawRefraction,
rawLighting,
rawGI,
rawSpecular.

Doing this you will be able to globally tweak the environment for all objects, or tweak material properties, much like you'd do in VRay, instead of just slapping on an overall colour correction.

After tweaking you can go back to the non-raw passes, just make sure you use you adjusted filters and raw passes.
diffuse = baseDiffuse * inverted reflectionFilter
reflection = rawReflection * reflectionFilter
refraction = rawRefraction * refractionFilter
lighting = rawLighting * diffuse (the one three lines up)
GI = rawGI * diffuse
specular = rawSpecular * reflectionFilter

Then add them all up as described above.


*Notes:
- I've added a base diffuse pass as the VRayDiffuseFilter is the bitmap colour multiplied with the inverse reflection filter, most people don't know this. The base diffuse here is now the colour as you've put it as the diffuse colour in the material, meaning it's now the same as the bitmap or colour swatch input. Usually the difference is not that noticeable, but it can be a big difference if you're not using Fresnel for example.
- I've added rawSpec as you can treat spec the same way as reflection with this setup, meaning tweaking the reflection filter will adjust specular as well.
- SSS doesn't always add up correctly, currently. Meaning the beauty might be different when adding up all the passes, correct me if I'm wrong. I think this is being fixed at the moment.
- You can render out the raw passes directly from VRay from 3.0 on. There were fringing problems before that, though keep in mind this note from the VRay help page:
"In order to render a correct Raw render pass you need to also render the corresponding main element and filter i.e. for Raw Reflection you need Reflection and Reflection filter, for Raw GI you need GI and Diffuse filter etc."

[joconnell]

Great write up Rens. Just curious if you have the filter passes in your setup linked to attempt to keep energy conservation going? In other words if a comper removes some reflections it's automatically adding back in some diffuse?

[Rens]

Thanks John! A bit overkill for the thread maybe hehe.

Well, by adjusting the reflection filter you will get the adjusted diffuse for free if you divide the diffuse filter by the inverted reflection filter beforehand, then tweak and re-apply that reflection filter to the reflection and the diffuse. For example if you set the reflection filter (meaning the reflection material property) to 1 and multiply with the raw reflection you will get full reflection. If you then multiply that inverted reflection filter with the base diffuse (or you could call it raw I guess), you will get zero diffuse. Basically it works as the blend map in a VRayBlendMat.

I'm guessing this is what (partly) happens in VRay to keep energy conservation, the raw reflection gets multiplied by the reflection filter, and the diffuse colour gets multiplied by the inverted filter, so it will always add up to one.

[joconnell]

Yep - I reckon this is well worth putting into a gizmo. So for the filter passes I'd need to use black white and gamma to allow proper control over ramp and amounts (though edge reflections always go to 100%, maybe tweaking white point shouldn't be allowed?), then a simple multiply for the colour elements like base diffuse / light / gi / raw reflect and refract? Since strength / amount is provided by the filters the other parts should only really be hue / tint controls?

It'd make pass management a bit easier too - we render as a sequence per element here so the compers can kill the overhead of any channel they don't use but maybe it'd be best to keep all the rebuilding related passes automated into a gizmo and having all the additional utility bits as copied in channels afterwards?

[super gnu]

This thread is going way off its original purpose, but very interesting! keep going! i wonder if i will ever need such complex control in post. im at the level of.. ill just rerender it. :P

[joconnell]

I wonder if the free version of something like fusion would work for you? Shimazake on the forum wrote an automation tool for photoshop to load in exr's and set the blending modes, for rens ideas above, you'd have to use linear dodge in place of add and just be careful to keep your reflection and refraction filters synced since there's no linking in photoshop.

[Rens]

Either the gizmo route or a tree that's copied in, I prefer the latter as you have more freedom. Then you can have different places for tweaking, one global for all the env properties and then one per element, with or without ID mask.

Yeah I'd say rebuilding as a tree or gizmo and then the utilities just copied in.

But I'll make a separate thread about this in the next few days with some nuke examples, it's edging on thread hijacking now.

edit: ah, some more replies while I was typing : )

[joconnell]

The notoriety grows