Help with creating a single EXR in VRAY 1.5

[dcullipher]

I feel like I am missing something very simple but I cannot see how to make a single exr file with all channels embeded.

Any tips on this process?

[instinct]

turn off Max's save image option. Turn on VrayVFB. Turn on "Safe to vrimg" option. Click the browse button, enter the filename and simply append .exr to the desired filename instead of vrimg or nothing. Then vray will write an exr with all channels embedded.

Regards,
Thorsten

[dcullipher]

THANKS! Man I knew it was something like that.

Chaosforum to the rescue again.

[lukx]

do I need any plugin to later open exr in PS cs3 with all the channels? I tried and it's just image with alpha.

[rivoli]

do I need any plugin to later open exr in PS cs3 with all the channels? I tried and it's just image with alpha.

yep, you'd need a plugin. ps can't show any channel of an exr apart from rgba. you might want to have a look at proexr:

http://www.fnordware.com/ProEXR/

[panthon]

I have tried this plugin but I dont know how to embed Noderender or Zbuffers inside the exr. I have added them as channels in both the extra channels of exr and the render elements in vray, but then in photoshop all I get is a bunch of useless greyscale maps.
Any success with this plugin?

And in AE or combustion?

[rivoli]

nope, I haven't tried it. no cs3 here yet (either ps or ae).

[sv]

i think nuke is the only commercial bit of software that can read multichannel .exr's. Photoshop will only show the alpha i think.

You could of course render to .vrimg, then use the converter to display all the channels in the file - at least then you know you have rendered them out properly, but you just need a bit of software to read them properly - again, i think only nuke will do this in a single .exr.

[instinct]

The plugin that was posted above is SUPPOSED to load all layers into PS/AE. No idea if it works tho. Nuke is the only app that does it out of the box tho. Fusion allows reading all channels but only one layer at a time. So you still have RGBA + Amount of elements read nodes (even though it is a bit of a relief to have one sequence on your fileserver heh). That still does create quite some overhead tho (reading a file 10 times sure takes longer then reading it all in one big gulp. Not to mention usability

Regards,
Thorsten

[gunny263]

running into this as well though I am getting a bit further perhaps.

Attached is a screencap showing the vrayinfo string as well as the layer structure imported into CS3 using ProEXR plugin

Seems as though all channels missing alias string are being discarded by ProEXR.
I also noticed exr images from Vray come in with really dark default exposures compared to just about everything else on the market.

[/img]

[panthon]

Well, ive been using the plugin for CS3 for a day and i have been able to import successfully a lot of -if not all- vraychannels into cs3 with 32 bit precision (float) and alpha channel.
The key was rendering the Exr from the Vrayframebuffer dialog (Vrimg) and changing the extension to ".exr" and then I selected the channels I wanted from vray render elements.



Edit: Not all channels are imported. NodeRender ID, Object ID and MaterialID are missing when imported in PROexr. Zbuffer is imported correctly.

[instinct]

I also noticed exr images from Vray come in with really dark default exposures compared to just about everything else on the market.

This is cause they are saved as linear EXRs instead of sRGB, wich is btw the way .exr is intended to be used. Just that PS and AE suck at working in linear space...You should be able to work around that by gamma correcting the images. Either in post or via VRays Color-Mapping.

Not all channels are imported. NodeRender ID, Object ID and MaterialID are missing when imported in PROexr. Zbuffer is imported correctly.

This is due to the fact that the ID channels are integer channels. Wich is supported by EXR as other arbitrary data channels. These are not really meant to be used with standard postpro techniques.

Regards,
Thorsten

[gunny263]

Hmmm..guess I don't use standard postpro techniques...
Material ID and object ID's are pretty important to me.
Guess I can always run a quick scanline pass to get what i need since that obviously doesn't benefit from the higher bit depth. Just would have been nice to eliminate the extra step.
Thanks for the clarifications.

[instinct]

I'd suggest using Multimatte for Mattes, works a lot better then the ID channels and is included with 1.5 Final

Regards,
Thorsten

[gunny263]

Tried it quickly - couldn't get it to work either. At least - not as I would expect it too. Would be nice to either use the render elements already available in Max or use a standalone version of Vray. This in between stuff is quite cumbersome