V-Ray Elements - Composite Diagram - Nuke - Edge Problem

[phizikl]

Hi,
Please take a look at these images.
I am able (finally!) to sucessfuly recreate all Elements including Raw&Filter elements, the only Issue I still have are the edges. The comped render looks great, if It werent for those edges. Unmultiply and premultiply dont work, at least the way I use it. I am sure this is a minor problem and can be easily solved, so if anyone is a regular at comping V-Ray elements in Nuke, please share the solution to this problem.

Thank You!

[vlado]

You are likely to get such issues any time you multiply two elements together and there is a sharp edge at the same place in both elements. One solution is to avoid multiplication whenever possible and just use the respective pre-multiplied element out of V-Ray (e.g. lighting, instead of diffuse*raw lighting). The other is to render at a larger resolution and then downscale the result.

Best regards,
Vlado

[sandykoufax]

http://www.vfxvault.com/vfxvault.com/Tutorials.html

I think this tutorial is helpful.
There are other diagram to solve some problems.

[phizikl]

thank you so much!

the solution is just to divide one of the passes before multiplying


i am quite suprised that no one here knows how to dothat!!!


and i would highly recommend including this information inthe vray documents---

its just a simple image, and it will help everyone get 100% original in nuke or wherever else....

just a graph showing all the vray elements including the raw elements, multiplied and added, plus the division to get rid of anti aliasing---


i KNEW there was a way to get it to work

[instinct]

I assume by "divide" you mean unpremulting ? Divide is a pretty generic term. In case you mean unpremulting this will only work for elements you have an alpha for. Wich you havent for many or only have them in very specific cases. Hence it may fix things in specific cases but not generally. Maybe i misunderstood what you mean so could you clarify what you are doing or post an example ?

Regards,
Thorsten

[phizikl]

by divide i mean a merge (divide) instead of merge (multiply) (not unpremultiply)

the acvtual mathematic function


i do think there is a UNIVERSAL composition that we can offer to artists, where u would theoretially only change the .exr and the outcome would be perfect


i will post pics later

happy to have the solution! great tutorial!

[instinct]

I dont see how that should work tbh. Dividing the RawReflection by the ReflectionFilter changes the whole reflection, no ? So even if it fixes the edges it would change the whole relfection and defeat the idea of recreating the RGB ?

[phizikl]

no, your dividing the double aliasing out of it
and then multiplying
watch the video

100% orignal RGB, no edge problems

http://vfxvault.com/tutorials/nuke_c...ch_01_h264.mov

[instinct]

4h left :P

[phizikl]

lol
i got mine in 20minutes

[instinct]

The Vid is still far away, but the media zip is in. And i still dont get it. The rightmost version is called "light and edges fix" But it doesnt work.

First of all it creates edges (just in different places) and secondly it generates negative Values in some places wich is an absolute no-go.

While it uses some tricks we use for special cases this doesnt seem like a generic fix at all to me.

Regards,
Thorsten

[phizikl]

im trying it now let u know if it owrks

[phizikl]

haha, well the one .exr i just tried, the diffuse x raw_gi doesnt even equal the normal GI pass, same for diffusexraw lighting and raw reflectionxfilter
each pass is slighty less dark than the original


really dont understand why they dont add up the same for any scene

[khoross]

Thx This was really helpful,after a few hours my comp was the same as original & no edges

[sukistar]

this works quite well:

(all the shuffles are connected to the nop1 "split" but have hidden inputs)