How do I export EXR with multi passes?

[tmcintosh]

Just wondering how to export to EXRs with all the selected passes/channels included in the 1 file? I know how to export the passes to separate files, but was looking for a more streamlined workflow.

Thanks!

[nizu]

Re: How do I export EXR with multi passes?

Hi,

I haven't tried myself , but i'm not sure if vray has an option to export directly 1 exr with all passes.

Instead there's the VRIMG format which includes all passes , and can be converted to EXR with a command line tool included in standalone..
(and you can specify how to split files or keep them in 1)

Also i think Blender nodes can't read arbitrary layers in an exr (only color and z-depth) ...so it would be of limited use for comp. in Blender..

[nizu]

Re: How do I export EXR with multi passes?

Hi,
some additional info :

you can save VRIMG from vfb 'save as' or using the 'multilayer' format option from VB output .

Then run the "vrimg2exr.exe" (included in standalone in the folder : chaosgroup\V-ray\-your-vers.-\bin\ )
Using default options will output an EXR with all layers (i think..) , same filename , in same folder.

In Ubuntu i just chose vrimg2exr.exe as default program to open .vrimg files , and it worked.

Too bad Blender didn't recognize all the passes (shows the AO pass as if it was the main color pass ..but they seem to be there)
Also, I haven't found any OS app that reads all the layers correctly , do you know of any ?

[tmcintosh]

Re: How do I export EXR with multi passes?

Hmm, thanks Nizu, I was afraid of that. Ideally I'd like to be able to export an EXR image sequence with my preferred render passes in the one file for each frame. I was also hoping to do the compositing in Blender using these images. Sound like a multistep process that may not even work correctly. I will give the vrim2exr.exe at try but how do you save a sequence of VRIMG files? Doing it manually one by one out of the VFB sounds incredibly tedious!

Cheers

[nizu]

Re: How do I export EXR with multi passes?

No need to do it frame by frame. For rendering sequences : 'multilayer' = Vrimg

In the output panel , where you normally set the format of auto-saved renders, choose 'multilayer' instead of 'exr' to get animations autosaved to vrimg.

Converting is quick: just choose vrimg2exr as default app to open .vrimg , then double click on the files to see the EXRs appear ( at least in Ubuntu)

I checked about blender support for multilayer exrs : it's there but only works for BI output : apparently BI EXR files have a special tag in them to tell blender to read the layers,
Maybe adding that tag will make the node editor read the channels ... even if they're named differently than BI's .
I'll look into that , if that works and can be automated the whole thing would be very handy..

[nizu]

Re: How do I export EXR with multi passes?

...continuing from previous post:

Seems it could be possible to open multilayer EXR from Vray in Blender Nodes , and get all the passes from one file.

-- Blender internal needs a 'tag' in the header of EXR file.
-- Vray standalone has an option to add tags to exr headers ( "blender multi pass" )

But :

-- first we need to output a vrimg and convert .. so the tag probably has to added after conversion ..
-- i can't seem to get the syntax right in vrscene to add tags to exrs, anyway...
-- blender multilayer exrs may have other requirements other than tags (still seems Aqsis render figured them out and solved this for their output files ..)

So ..possible , but i don't think i'll manage to solve this

[tmcintosh]

Re: How do I export EXR with multi passes?

@nizu - thanks for looking into this, hopefully it's technically not that difficult to accomodate the blender EXR format. I think it would make vray output much more Blender friendly, if we could do native compositing with the files. I suppose you still can do it if you output all separate files for the render passes, it just seems so unwieldy... Maybe bdancer could have a look at this some time!

[Animotor]

Hi,

Has this thing progressed since 2011? I've tried different settings with the EXR format but I always get the passes in separate files and loading them into composition is pretty tedious.

I tried to look for the Vrimg2exr program, mentioned in the earlier posts, from my V-Ray Standalone folders but no luck. It seems it is a Windows program, am I right? Is there a way to do the same conversion on Ubuntu or does some one know how to import vrimgs to Fusion?

[JuhaW]

Once you set your Fusion nodes, all render passes you'll need. Next time you render your new project, use the same save name/filepath than before, reload Fusion template and hoplaa, all your render passes are now loaded !

[Animotor]

Thanks JuhaW for the solution.

By creating the render passes readily in the Blender start-up -file, I can make my pipeline faster. For Fusion I found from another forum, how the file paths can be made relative. From Fusion>preferences>Path Map one must check the "enable reverse mapping of non-user path" checkbox. This way I can have my projects in separate folders with matching renderfile names. Then I can create a "template" Fusion -file that I can use.

[JuhaW]

Thanks for further information, I'll test that relative path thing.