Specifications for EXR-format: Maximum amount of pixels

[kosso_olli]

Hey,
I have a short question here. I need to render some super high res image, the resolution is 35000x19800px. The rendering itself works just fine, but when I try to save the render as EXR, Max instantly crashes. I tried to save directly from the VFB. I get the EXR options dialog box, and when click OK, Max is gone. Does the EXR file format have any limitation regarding resolution or pixel count? Besides the rgb channel, we also have the usual render layers.

[vlado]

I think 3ds Max has a limitation of 32767 for the image width/height. Does work if you save to EXR file from the V-Ray raw image output?

Best regards,
Vlado

[kosso_olli]

Vlado,
I typed the resolution into the V-Ray dialog, I am not getting the resolution from the Max frame buffer. That buffer doesn't let me type in anything bigger then 32767, thats right. I didn't try ra image otput yet.

[kosso_olli]

I get an error message as soon as the render solution exceeds 32767px: Cannot create bitmap file. I will render slightly below this value, everything is fine.
I didn't try raw image output as EXR, because we need the render elements as seperate files. We don't have Nuke or something like that which can read a multichannel EXR.

[bhm]

What about raw output to .vrimg and using the VRImgToExr-converter tool?

[kosso_olli]

That is what we are trying to do now.

[SnipeyX]

...we need the render elements as seperate files. We don't have Nuke or something like that which can read a multichannel EXR.

FYI in case it helps for workarounds - the ProEXR plugins for Photoshop, After Effects, and Premiere are free: https://www.fnordware.com/ProEXR/ If you just needed photoshop there's also https://www.exr-io.com/

[kosso_olli]

We can not get any method to work correcty. Both multichannel exr and seperate exr channel are crashing on saving. We get a dialog from Max, which tells us about an I/O error because of bad memory allocation. We have around 40GB of free RAM while saving, though.
Right now we are rendering each image in two pieces, 50:50 at a resolution of 17k.
I also tried a vrimg, but that file was 53gb after saving. The converter tool crashed instantly.

[^Lele^]

you may simple not have the required RAM to save the image (the vrimg size is a good hint).
Try with a humongous swapfile, see if that helps.

This is why there's tiled, bufferless rendering, by the way.
Using it often, and early, saves on headaches.

[kosso_olli]

As I said, 40gb of free RAM. This is not enough to save an image? Er, okay...
I also tried disabling the memory frame buffer. Same problem, same error message.

[^Lele^]

As I said, 40gb of free RAM. This is not enough to save an image? Er, okay...

Depending on compression options, and indeed number and type of AoVs, 40Gb may be too small for a 56Gb compacted file.

I also tried disabling the memory frame buffer. Same problem, same error message.

You must have been doing something wrong, i just wrote to disk a 50k px square image with tiled rendering using less than a Gb of ram for an empty max instance and the rendering of an empty scene directly to disk.

[^Lele^]

You must have been doing something wrong, i just wrote to disk a 50k px square image with tiled rendering using less than a Gb of ram for an empty max instance and the rendering of an empty scene directly to disk.

No, i was wrong.
If writing an EXR, the data writing process doesn't start for a while (but the file name gets written right away, hence my confusion), and max crashes as that begins.
If writing a VRImg file, the crash is instantaneous on first bucket writing.
Max 2017 and latest nightly.

[kosso_olli]

No, i was wrong.
If writing an EXR, the data writing process doesn't start for a while (but the file name gets written right away, hence my confusion), and max crashes as that begins.
If writing a VRImg file, the crash is instantaneous on first bucket writing.
Max 2017 and latest nightly.

This sounds exaclty like our error. We noticed it for the first time on Backburner: The job itself was finished, but the files were not written after two hours. We then checked the host and found the error message described above. This also happens locally on my machine. We could send a file showing the problem, if needed. No NDA this time, so this should work.

Vrimg works fine though, but it is the conversion process that doesn't work because of the file size.

[^Lele^]

Vrimg works fine though, but it is the conversion process that doesn't work because of the file size.

Lol i'm so confused, as it crashed for me in tiled mode... XD
But yes, at least i managed to repro one of the issues, and with an empty scene at that (for the once we don't have an NDA problem, of course. -.-').
Many thanks for the pointer!