vrimg2exr problem

[Shimakaze]

Been playing with 1.5 final and have been running into problems with the new vrimg converter. When exporting the RGB color channel and opening it in Photoshop it always turns up as a blank (completely transparent) picture. If I just do a straight conversion without specifying a channel name I get a working RGB color picture albeit with the background removed because of Photoshop's silly handling of alphas in exr pictures.
So my question is, why doesn't this work as it should?
my command looks like this:
vrimg2exr in_name.vrimg outname.exr -channel "RGB color"
the file gets quite big so it obviously contains something. just nothing shows up in Photoshop.
Oh and other render elements appears to work fine, though I haven't tried that many yet.

[vlado]

This is because when you convert just the RGB Color, the converter does just that and ignores the alpha channel (actually the alpha in the resulting .exr file is black, which is why you don't see anything in Photoshop).

So you'd need to also convert the Alpha channel separately, and use that in photoshop as the RGB channel mask.

Best regards,
Vlado

[Shimakaze]

Hmmm I see. That solution doesn't work though because Photoshop processes the pictures on import and actually alters the pictures instead of just setting an alpha channel. So it ends up deleting the entire picture since it believes everything should be transparent. And even if you add an alpha channel to the picture afterwards it can't bring back the deleted pixels.
It's the same reason why you can't just use a straight EXR in photoshop, since it contains an alpha channel that makes photoshop completely remove the background.
Perhaps an option could be added to the vrimg2exr tool to write the output file without any alpha channels? Something like -noalpha for instance. Or to set the alpha to pure white instead of pure white. That should fix the problem.

[vlado]

I see; setting the alpha to white should solve the problem then... and there is no way to make PhotoShop ignore the alpha channel on import? (I'm not familiar with PhotoShop, I've been using Corel PhotoPaint myself).

Best regards,
Vlado

[dlparisi]

What version of photoshop are you using, CS2, CS3? At some point Adobe seems to have changed (i.e broke) the way photoshop imports EXR files and treats the alpha as transparency and removes it from the image during import as you describe. It's been a while since I did this so I may be mistaken, but the simplest solution is to get an earlier version of the OpenEXR.8BI file from a previous version of photoshop. The one I have installed is dated 3/22/2005 so I'm not sure what version that corresponds to. It imports the full image and just puts the alpha in the alpha channel.

P.S. The ILM OpenEXR plugin http://www.openexr.com/downloads.html also brings it in correctly but for also brings it in as 16bit rather than float.

[Shimakaze]

I use CS3 and it's still doing it in the silly way. I used to use Corel Photo-Paint back when it was in version 8 or something like that. perhaps I should get back to that program... maybe some day.
With Photoshop you don't get any choices when you open exr files. Any alpha that is present is automatically used to irreversibly alter the pixels, meaning the alpha would have to be changed before opening it in Photoshop at all.
Using another plugin/program that doesn't support float kinda defeats the purpose...

[idtools]

Hi all,

I went through the forum just now because I have a problem quite similar on RC3. The deal is that I'm not in test, I went through a 3 hours render and my RGB channel is all burned, when I open the exr in Photoshop CS2 or in the Viewer from Max. It's not totally black there is a few shadows around.
As Shimakaze, the background is OK and all the others channels are good.
My test renders via the VFB were OK.
I used the vrimg2exr tool many times without a problem.

I'm sorry but I don't well understand the process you explain here.
Please help to save my week-end.

Arno

[dlparisi]

I use CS3 and it's still doing it in the silly way. I used to use Corel Photo-Paint back when it was in version 8 or something like that. perhaps I should get back to that program... maybe some day.
With Photoshop you don't get any choices when you open exr files. Any alpha that is present is automatically used to irreversibly alter the pixels, meaning the alpha would have to be changed before opening it in Photoshop at all.
Using another plugin/program that doesn't support float kinda defeats the purpose...

You misunderstood me - CS2 and CS3 is where the problem started. Photoshop used to import EXR's correctly but since then it treats the alpha channel as transparency and deletes it from the image when opening it. You'll need the openexr.8bi file from an earlier version of photoshop. Otherwise there's this...http://www.fnordware.com/ProEXR/

I don't know why the ILM version of exr opens it as a 16bit file, seems like it needs to be updated or something. Probably from when photoshop didn't support float images.

[idtools]

Sorry for my last post...
Max Exposure Control was on.

Hope you'll find your solution
Arno

[Shimakaze]

You misunderstood me - CS2 and CS3 is where the problem started. Photoshop used to import EXR's correctly but since then it treats the alpha channel as transparency and deletes it from the image when opening it. You'll need the openexr.8bi file from an earlier version of photoshop. Otherwise there's this...http://www.fnordware.com/ProEXR/

I don't know why the ILM version of exr opens it as a 16bit file, seems like it needs to be updated or something. Probably from when photoshop didn't support float images.

Nono I understood what you meant :P I don't know whether a CS plugin would work in CS3 though... Mind sending me it? Anyway I tested the ProEXR plugin and it worked, however it requires you to hold down the alt key every time you open an image which is quite annoying. It's still a good option though, but I'd much prefer having the option to fix this directly in the vrimg converter. After all when saving out separate layers directly from V-Ray it doesn't have this problem at all. It's really only when using vrimg files which is kinda silly.

[sv]

Shimakaze,

did you ever fix this problem?
i've tried reverting that OpenEXR.8BI back, but it's not working...

[teabag]

happens in cs3 from the start for me....
really mad at adobe....
has anyone tried ProEXR?

[teabag]

have tried proexr demo now...and guess what....it does the same thing!!!! cant believe that

[vlado]

Well, in any case, I've modified vrimg2exr to omit the alpha channel when exporting just a specified RGB channel.

Best regards,
Vlado

[sv]

Well, in any case, I've modified vrimg2exr to omit the alpha channel when exporting just a specified RGB channel.

any chance you could actually make this an option rather than a default? - i find it really handy that the extracted exr has an alpha channel in it, even if CS3 can be a pain in the a*se with it sometimes - with CS2 it handles it perfectly....