vray 2.4 writing bad exr's/png's from Deadline?


Hey all,

At my work, we’ve been coming into a problem over the past few months where vray appears to be writing bad exrs and pngs from our renderfarm. Photoshop just wont open the file citing a "program error’.

Nuke indicates ‘Unexpected data block y coordinate’ in the file.

Interestingly, I’ve noticed that often times I can open the exr in mental ray’s imfdisp.exe utility and then just resave the file and its fixed. wierd…

Its happening alot lately and we’re finding more and more of our footage to be broken in this fashion. We’re using Deadline as our farm manager. Thought Id reach out to the community on this one. Has anyone ever encountered this problem before, maybe know a fix?



I have the exact same experience as you. Never seen it before. I just rendered (3DS Max+vray 3+backburner) a huge image for many hours and now it won’t open in either Nuke or Photoshop. :hmm:



Hey Thomas, thanks for the reply. We noticed recently that it seemed to be a repeatable error when we were overwriting footage that was already there, but it didnt seem to happen if it was writing new files. Any chance this is also the case for you?


No, this is the first render of this image.
I’ve resubmitted with slightly changed settings. Still scanline image, not tiled (because of Nuke) if still no success I’ll try with tiled.


Hi JasonA
This MR utility, imfdisp.exe : I don’t have it, or I can’t find it. Is it something you can zip and share somehow? I’ve just done a new render, same problem. Now I’m doing a tiled version of the exr, but I wont know the result before Tuesday morning.



Hi Thomas,

imf_disp.exe is actually part of the normal Maya installation, in the mental ray folder. Its one of about 6 small utilities mental images provides. I see youre on 3ds max, perhaps check to see if you have a separate installation folder for mental ray, if you do these utilities would likely be in the …/bin/ folder. I’m not sure if it can operate correctly without being installed, but I can send it over, PM me an email address please.

We’ve also being noticing that we get bad PNGs from the farm as well (we use them for masks), have you noticed this problem with other formats beside EXR?


Which Nuke version are you using? How long are the names of the render elements in your scene? Some versions of Nuke use an older version of OpenEXR and will refuse to read files where render elements have more than 31 characters in their names.

Best regards,


Ok, now I found the file, it was the underscore I missed :slight_smile:

Only seen this with exr.

I can open the file now, but only the RGBA “element”, not any other render element within it.
But the whole image is not saved. When I rendered it I had render window turned on, so I could follow the progress, and everything was rendered as expected, but what is saved in the file is only a portion. Maybe it’s the reading by imf_disp.exe which causes it.

Vlado: the element names are short, not changed from what Vray suggests by default.



Hi Vlado,

For us, we’re not using any render elements, just the main RGBA channel exr. Im looking at our ‘bad’ exrs in Nuke 7. To be clear, this only seems to be happening to us when we render from our renderfarm. If I batch it locally, they’re always fine.

While the imf_disp.exe solution seems to work for fixing the exr’s. its a clunky solution at best when there’s many exrs having the problem. Alot of manual, open, resave, open resave etc. Its painful to do this when i have 10s or 100s of files to fix.

Right now we havent been able to determine if its a vray problem, a deadline problem, or something with our network.


For info: I’ve now re-rendered the image, but this time not a region render. Problem solved.
I also had slighly higher sampling threshold to speed up the rendering, but I can’t see what that would change.

Hmm, I hope it’s just one of those things I will not see again, now that it’s never been a problem before.



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