Extracting multimatte channels

[tricky]

So I can extract any multimatte channels that I have saved to a vrimg file, right?

[tricky]

Answered my own question - yes it does.

I useful tool would be a GUI for vrimg2exr which will show you the image and all the rgb channels and give export options for them all. Does this exist or is it in the pipeline?

[dbuchhofer]

lele had created one but stopped working on it as apparently there is such a thing in the works, so he decided to spend time on different stuff when/what/how it will come available to us peons i haven't a clue

also in the 1.5 stuff if you have that, you can save directly to .exr now

[dbuchhofer]

also, a batch file can be used if you want, you just have to edit the batch file to match the names of your channels and it will process them when you drag the vrimg file onto the .bat file

Edit to suit, i used some silly names I guess it would make sense if you used a standardized naming scheme when doing the Render Elements

"C:\Program Files\Chaos Group\V-Ray\3dsmax R9 for x86\tools\vrimg2exr.exe" %1 "%~fn1_Color.exr" -channel "RGB Color" -sRGB -half
"C:\Program Files\Chaos Group\V-Ray\3dsmax R9 for x86\tools\vrimg2exr.exe" %1 "%~fn1_Multimatte1.exr" -channel ColumnCarpetCeiling -half
"C:\Program Files\Chaos Group\V-Ray\3dsmax R9 for x86\tools\vrimg2exr.exe" %1 "%~fn1_Multimatte2.exr" -channel FabricGlassExt -half
"C:\Program Files\Chaos Group\V-Ray\3dsmax R9 for x86\tools\vrimg2exr.exe" %1 "%~fn1_Multimatte3.exr" -channel Trim -half
"C:\Program Files\Chaos Group\V-Ray\3dsmax R9 for x86\tools\vrimg2exr.exe" %1 "%~fn1_Multimatte4.exr" -channel DropclgClgTrimPainting -half
"C:\Program Files\Chaos Group\V-Ray\3dsmax R9 for x86\tools\vrimg2exr.exe" %1 "%~fn1_Multimatte5.exr" -channel paintsGreyblueTerraWhite -half
"C:\Program Files\Chaos Group\V-Ray\3dsmax R9 for x86\tools\vrimg2exr.exe" %1 "%~fn1_Multimatte6.exr" -channel PlantsTables -half
pause

[tricky]

Ahhh - very clever. Will give it a try.

[tricky]

So now that vray (1.50.00) can directly save EXR files, will the exr contain all the multimatte channels and any other renderelement channel that I include?

If so, when I open the EXR in photoshop, should all those channels be there?

Also, will the exr also contain the floating oint data - ie I can re-expose in photoshop?

(I am testing now to try and answer these questions, but my early results have failed for whatever reason. I have probably got a setting wrong somewhere)

[tricky]

...mmm...can't seem to get the exr to save the multimatte channels...

[rivoli]

all the channels should be there, but ps can't read any channel of an exr apart from rgba. I think there's a plugin called proexr that does just that both for ps and ae.

as long as you don't clamp the output (or save in 16bit), all the full float data should be preserved.

[tricky]

Could anyone explain how to do the batch routine above? Do all the " need to be in there and what does the '%1' and %~fn1 mean????

vrimg2exr.exe is on my c:drive at address
C:\Program Files (x86)\Chaos Group\V-Ray\3dsmax R8 for x86\tools\vrimg2exr.exe

my vrimg file is on a network drive, path:
K:\GENERAL\BAL002 - 50 St\Renders\IM01 - Exterior\BAL002_IM01_base150000.vrimg

the vrimg file contains 3 multimattes named "matte1" "matte2" and "matte3"

How would I auto-extract these using a batch utility?

[rivoli]

the batch above extracts channels as exr from a vrimg file (the -half command will actually save them in 16bit instead of 32bit).
if you have already saved a file in exr format insted of vrimg, you don't need it. probably what happens is that you have all the channels stored in your exr, but opening it with ps won't halp, because it can't show any of them (apart from rgb and alpha).
you're probably better off splitting the rendering, and saving any channel as a different exr.

[tricky]

I like the idea of saving to a vrimg file and having a batch utility that I can run to extract everything in one process - the only proiblem is with my paths - they are network locations with long path names and I am just not sure how to get a batch utility to read these path names.

[peakyfreak80]

Tricky - Did you ever figure out how to extract the images from the network locations? I'm having the same issue myself.

Thanks
peakyfreak