Nuke Multichannel

[bradon]

I'm trying to recreate the rgb render from maya vray using Nuke Multichannel comp. I am using the formula.

GI + Light + refract + reflect + self Illum + specular.

I have a tutorial with example where this worked however in my case its not producing a 100% replica of my specific vray RGB render so maybe there is some setting that im missing in my render? or some pass that I'm missing to do this correctly? anyone direct me how to do this better?

here is the nuke graph I can provide the exr for anyone who wants to try. I would say the main difference is the multichannel composite the reflections look brighter and the overall saturation is more.

set cut_paste_input [stack 0]
version 6.2 v1
BackdropNode {
inputs 0
name BackdropNode2
tile_color 0x4888ff
label "Merge rest of passes: \nLight + Refraction + Reflection + Caustics + Self Ilumination + Specular + Atmosphere"
selected true
xpos -1353
ypos 595
bdwidth 862
bdheight 316
}
BackdropNode {
inputs 0
name BackdropNode11
tile_color 0x9b3400ff
label passes
selected true
xpos -1360
ypos 415
bdwidth 877
bdheight 172
}
Read {
inputs 0
file Y:/_PROJECTS/2010/0091_maytag_alpha/06_3D/Maya/images/tmp/AlphaFilePasses/Hero_Cam/masterLayer/masterLayer.exr
format "1358 1000 0 0 1358 1000 1 "
origset true
version 1
colorspace linear
name Read1
selected true
xpos -1001
ypos 212
}
set N1e765e20 [stack 0]
push $N1e765e20
Dot {
name Dot7
selected true
xpos -967
ypos 320
}
set N1e766380 [stack 0]
add_layer {specular specular.red specular.green specular.blue}
Shuffle {
in specular
in2 alpha
out2 alpha
name Shuffle19
label Specular
selected true
xpos -593
ypos 504
}
push $N1e766380
add_layer {selfIllum selfIllum.red selfIllum.green selfIllum.blue}
Shuffle {
in selfIllum
name Shuffle20
label "Self Ilumination"
selected true
xpos -715
ypos 507
}
push $N1e766380
add_layer {reflect reflect.red reflect.green reflect.blue}
Shuffle {
in reflect
in2 alpha
out2 alpha
name Shuffle22
label Reflection
selected true
xpos -865
ypos 503
}
push $N1e766380
add_layer {refract refract.red refract.green refract.blue}
Shuffle {
in refract
in2 alpha
out2 alpha
name Shuffle24
label Refraction
selected true
xpos -988
ypos 504
}
push $N1e766380
add_layer {lighting lighting.red lighting.green lighting.blue}
Shuffle {
in lighting
in2 alpha
out2 alpha
name Shuffle26
label Light
selected true
xpos -1111
ypos 504
}
push $N1e766380
add_layer {GI GI.red GI.green GI.blue}
Shuffle {
in GI
in2 alpha
out2 alpha
name Shuffle28
label GI
selected true
xpos -1287
ypos 505
}
Merge2 {
inputs 2
operation plus
name Merge6
label "GI + Light"
selected true
xpos -1134
ypos 685
}
Merge2 {
inputs 2
operation plus
name Merge8
label "+ Refraction"
selected true
xpos -975
ypos 710
}
Merge2 {
inputs 2
operation plus
name Merge9
label "+ Reflection"
selected true
xpos -852
ypos 749
}
Merge2 {
inputs 2
operation plus
name Merge11
label "+ Self Ilumination"
selected true
xpos -723
ypos 799
}
Merge2 {
inputs 2
operation plus
name Merge12
label "+ Specular"
selected true
xpos -608
ypos 845
}
push $N1e765e20
Viewer {
inputs 3
input_number 1
input_process false
name Viewer1
selected true
xpos -349
ypos 555
}

[bradon]

also tried this method with raw elements. but its still not producing an identical result as the rgb render.
http://vray.info/tutorials/basiccomping/

[bradon]

Ill try to break it down a bit.

here is GI compared to RawGI * Diffuse

Im told GI = Raw GI * Diffuse. should be identical but they are not. notice GI is darker than the two 2 combined passes.

not that comparing these passes gets me anywhere. I'm still ultimately trying to match the rgb render exactly if i can. but if figure you got to build this brick by brick.

[bradon]

can anyone tell me if this is in all cases possible to reconstruct a vray render in nuke using the passes? perhaps what I'm trying to do might not work in all cases. I have seen some vray renders reconstructed to give an identical result. but perhaps the specifics of my GI and lighting/material setups prevent re-constructing an exact match?

[bradon]

here is the multichannel file. can anyone tell me if the passes rendered properly and if I can composite this in a node based compositor, nuke fusion etc. using the render elements to recombine to achieve and exact rgb render?

http://www.paraportable.net/files/masterLayerFIX.zip

[Metzger]

I posted before about this and never heard back.

http://www.chaosgroup.com/forums/vbu...r-Element-Math

RAW GI * Diffuse should be the same as GI but it isn't. Same goes for Raw Light * Diffuse, and Raw Reflection * Reflection filter. I hope there is a good explanation from Vlado. I woud love for that breakout to work correctly. It has been like this for a few years.

[Mr.Hoo]

I recently did a composite with raw elements and hadn't the feeling something would be wrong - but I will have a look tomorrow, if I see differences...

Cheers!

Dominik

[vlado]

Everything works fine for me as well. If doesn't, then it usually means that some color correction is happening along the way that distorts the linear data - either in the renderer settings, or in the compositing application.

Best regards,
Vlado

[vlado]

here is the multichannel file. can anyone tell me if the passes rendered properly and if I can composite this in a node based compositor, nuke fusion etc. using the render elements to recombine to achieve and exact rgb render?

Can you attach the Maya scene as well?

Best regards,
Vlado

[bradon]

Yes I have uploaded to FTP site for you and email you the log in details. Many thanks Vlado.

Bradon