Rendering and Stitching Issues with .CXR Files in Backburner and Corona Renderer

[LazyViCE]

Good time of day, everyone!

I spent about 7 hours on the forum trying to figure out and solve my problem. My problem:

1. I have a very heavy scene for which I need 80GB of RAM, and rendering takes a very long time, or 3ds max crashes.
2. The scene contains a large number of render elements, such as LightMIX, and I really need them.
3. I'm trying to render the scene in Backburner with the "Split Scan Lines" feature enabled.
4. As a result, I get several pieces of .cxr files that refuse to properly merge into one .cxr file, as it happens under normal conditions.

To be more specific:

* I get one file that has no passes and is not displayed in terms of lighting as it should.
* and I have, let's say, 5 pieces of images, in which everything is fine, but they do not stitch together. They just lie alongside all the passes and LightMIX, but don't merge into a single .cxr file.
Reproducing the problem is as easy as pie:

1. Create a simple room box.
2. Add some signature teapots.
3. Add light sources.
4. Add light sources to LightMIX.
5. Try to render all this into .cxr as usual, but through Backburner with "Split Scan Lines" enabled.
6. Get a headache.

Software: 3ds max 2024, Backburner 2019 (latest available), Corona 11.1

Is there any way to finally deal with this task?

P.S. There is a script in the some thread that allows saving the .exr format somewhat adequately, but I didn't understand if it's possible to do the same with the .cxr format. With .exr, I barely managed to cope with the script, and even then, it's such a workaround...

[maru]

Hi, by default, your Backburner job should:
- render all "pieces"
- then automatically stitch them and output a single CXR file
- this CXR file should be openable in CIE and should contain all render elements, LightMix, etc
So perhaps you do not need to manually stitch the CXR pieces at all?

If you render with Backburner and enable the option to keep temporary files, this will also save the individual pieces for you. CIE can stitch images, for example render regions or Corona DR data, however it requires specific metadata for this as defined in the EXR standard ("display windows" and "data windows" - https://openexr.com/en/latest/TechnicalIntroduction.html ). If backburner does not save the pieces with that necessary metadata, then unfortunately we can't do anything about it.

Perhaps using different software than Backburner would work in your case, such as Deadline or Pulze.

[LazyViCE]

Thank you for trying to help. I'll also consider the option of replacing Backburner later on.

So! I don't want to stitch the result manually; it's almost impossible to do so. And yes, Backburner should stitch everything automatically, which usually happens.

I seem to be misunderstood... The essence of the problem is clearly outlined in the previous post, along with how to reproduce it. But I'll reiterate:

At the end of the job, I should receive 1 file in CXR format that includes all layers, passes, metadata, and elements.
But this doesn't happen if I add Backburner to the pipeline and enable the "Split Scan Lines" feature.

---
This issue is not new at all. There's already a post where they tried to solve this problem and wrote a script that was supposed to make Backburner save properly, but these workarounds ONLY work with EXR files, and even then, it's far from the best solution.
https://forum.corona-renderer.com/index.php?topic=25686.30

[maru]

I can confirm what you are saying.
I looked into it some more (including rendering CXR strips and stitching them through 3dsmaxcmd), but I could not get any satisfying results. Like you are saying: you end up with a bunch of "correct" strips or a single incorrect image. Unfortunately, the process of splitting an image into strips and stitching them is handled by 3ds Max so it is outside of our control.
I can only suggest using Deadline or Pulze. If you encounter issues with that software, you can contact their support and get proper help.
Another idea is upgrading RAM - as far as I understand the main reason why you are splitting your image into strips is running out of RAM.