Camera flickering

Hi! I’m seeing all the cameras in my simulation flickering on the right border. I’ve seen this using the latest version, desktop and container version and in multiple computers, so I assume this is just a bug or a misconfiguration.
Is this a known bug? I’m using the simulation with Replicator, and I see the issue in the output too.

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I just realized this does not only happen on the right but also in all the other borders.

@christianbarcelo i have not seen this happening on my end as another user. could you mention the Issac Sim version you are on as well as any driver/hardware info? and does this occur as soon as you start Isaac Sim or could this be a scene-specific cause? is there any way to repro in other scenes?

I’m seeing the same, though a bit less visible (at the bottom). My environment:

In my case the flicker happens when the sim is playing, does not happen when paused

Same thing happens to me: I just run the hello world demo:

  • Ubuntu 22
  • Isaac 2023.1.1
  • NVidia drivers 535.171.04

Here’s another video with the Cloud Maker demo that comes with Isaac Sim. Worth mentioning this happens with RayTracingLighting.

I’m on Ubuntu 22.04, Isaac 2023.1.1 and Nvidia drivers 535.171.04

Hello all!

EDIT: the original setting solution I posted here is not exposed anymore and should not be used. This is a known bug (multiple actually) that have since been addressed. This will be fixed in the next release of Isaac-Sim, when we move to the updated render pipeline. Please look forward to it! :D

I have a hypothesis about what’s going on but I haven’t verified it yet. TlDr; I think the quantization steps in whatever anti-aliasing algorithm we are using (maybe this one?) is picking up the deficiency of “RTX-photons” (the ray samples) that occur near the edges of the render. It appears to be exacerbated by movement, which I think might also be suggestive of this.

I’ll update with more information. Hope this helps!


This is adding a lot of unexpected noise in our SDG pipeline, is there any preventive solution? Was this present in 2023.1.0 or going back on the version would not help?

Edit: Thanks for the quick response by the way!

I feel your pain on the SDG pipeline. I didn’t realize that the solution I found was for internal testing only and should be discouraged for anything production level. This is because of how the test configuration affects the render pipeline, and the downstream issues it might cause. The best solution would be to use the latest version of Isaac-Sim when it releases “thoon”.

Another stopgap I found was to increase the render sizes by a few pixels and then crop. In your SDG pipeline this would be a change on the camera sensor settings, and then a crop node in your omnigraph before you actually save the data to disk. I don’t know if there’s already a crop node, because I wrote my pipeline as an extension, so I just used numpy / pytorch. You could either write your own or use a script node, which should also work.

Ok I’m testing the possible values for the antialiasing and given it’s a controlled environment, I might give them a try even if they’re meant for internal use only. Thanks for the pointer, it was really useful.
For the record, the value that worked the best for me is 4. The others either kept adding the flickering or made the whole scene darker.

On another note, and even tho it’s not exactly the same (let me know if you want a different ticket for this) my app is running containerized. Something I noticed is that running Isaac in the host WITH PATH TRACING makes the flickering go away BUT, attempting to use PathTracing within the Docker makes Isaac Sim crash with the following messages:

Do you know where the problem could come from? I’m checking now if there’s any setting to actually disable the denoiser or something like that.

looks like the crash was because you ran out of VRAM. given the nature of path tracing, which is more computationally more expensive than RTX-Realtime, it’s something that could likely be the cause.

and when you are using RTX-Realtime, have you tried disabling the denoiser to see if it has any visual impacts in the viewport?

I don’t think so because:
1- The same scenario runs just fine with Path Tracing locally
2- It seems the lack of VRAM is actually caused by the first error shown. The denoiser cannot load the weights, and might retain resources and spawn a new instance again that fails over and over again consuming resources, until ERROR_OUT_OF_DEVICE_MEMORY is thrown.

Do you know where the weights are stored? Maybe I can pick them from my local installation and put them into the container, unless it’s being consumed some other way.
I’ve tried disabling the denoiser when instantiating the SimulationApp but the images are extremely noisy. Is there anything else I’m missing? Cannot I disable the denoiser without seeing such a crappy result?

Any update on this? Since RT makes the borders of the camera glitch, I would like to be able to use Path Tracing, and that’s not possible right now from Isaac Sim’s container.
I’m creating a separate ticket for this, but given the context of the ticket I think it would be valuable to leave the data here too.

This should be addressed in our upcoming release. Please look forward to it! :D

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