Light Linking Issues

Hi!

I’m trying to use light linking to exclude a floor in Omniverse Composer (2023.2.5) and a yellow hue appears on the floor which is otherwise successfully excluded. I have a disc light illuminating the ground from above. I have included a screenshot with the light causing issues turned on and off. No lights have any color value. All have RGB values of 1.0, 1.0, 1.0. Color temperature is disabled on all lights.

This is likely a bug as I can get it to disappear sometimes by enabling and disabling some settings, but I can’t fix it consistently. Any tips, confirmations, or reliable work arounds would be helpful.


Hi there and thanks for your question. A couple of things. Light linking doesn’t work in the real time mode. It only works in path racing mode. Second of all it looks like it’s a very diffuse reflection on the floor so even if the light is actually disabled, it is picking up something. If you move the light up and down, do you see the yellow reflection move with it?

Even if it’s excluded, can you try two things. 1) make the floor completely reflective and then completely non reflective and see if you can identify it. 2) go into the light properties and toggle “diffuse” and “specular” and see what that does.

Also you can always just send me the usd file and I can take a look.

Hi Richard!

Thanks for jumping on this. To note your first concern. We are using path tracing only. The yellow reflection does move with the light.

  1. I tried making the floor completely reflective (maxing the specular value to 1.0). This actually killed the yellow tint but I suspect this is a temporary fix. As I mentioned I can get rid of it sometimes by toggling things on and off, but my final settings are never changed. Sometimes I’ll go from a perspective view back to camera view and it’ll be there again.
  2. There is no toggle on the light settings for diffuse and specular. Do you mean setting the Diffuse Multiplier and Specular Multiplier to 0.0?
  3. What’s the best way to share a file?

Yes, for .2. You are correct that is what I meant. If you want to simply collect the file using the command “file > collect” from the menu, then you can send me the zip file. If it’s very small directly here, or you can attach it to any standard file delivery system like dropbox, etc.

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Collected_LightLink.zip (6.3 MB)
Here you go. Another thing I’ve noticed is that once a “workaround” has been used to kill the yellow, it won’t work to kill it again once it has returned. Currently, I’m comping all of my renders over a clean plate of the floor.

Followup question: y’all aren’t developing Composer anymore though, right? Even if this is a bug, I can’t really expect a fix, no?

Actually, you are using the old version. The new version is 106.2, soon to be 106.3. However this is not on launcher. This is on our GitHub page. You can download it and build Composer yourself. GitHub - NVIDIA-Omniverse/kit-app-template: Omniverse Kit App Template

Let me have a look at your file as well.

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