Ray Traced Lighting Issue

Development Rendering
1

We recently came upon a problem with RTX lighting in our game and I have been unable to solve it. We’re getting a weird effect that almost looks like Z fighting, except it’s not. It seems to become more exaggerated the further we are from our origin point. We do have world composition and world origin rebasing turned on for our game. For reference, this issue wasn’t happening before and I’m trying to track down what we might have changed to make it happen, but I just can’t. It only occurs when moving.

Here’s a video of what’s going on:

When I looked at the back of the ship at around 0:25, the world origin shifted, so the problem went away for a tad bit. We have a shortcut to toggle RTX effects on/off, which I start toggling at 0:39 to show the difference. It definitely is only appearing with ray-traced lighting and I’ve attempted to narrow it down, but I just can’t find it. I’ve tried:

  • Toggling all ray traced post process settings we have active on/off
  • Changing ray traced samples and bounce amounts
  • Turning off static shadow settings
  • Upping light map resolution
  • Adjusting source angle of our directional light (which lights the scene)
  • I’ve attached a point light to our player ship with the ship as its parent and the effect happens with the point light as well

Any idea what might be causing this?

2

Quick update:

After running through revisions of our builds, things just got even more confusing (or more clarifying, depending on your view). We had a packaged build that ran just fine without this lighting issue. It was packaged using 4.22.0. Since that packaged build, I have updated to 4.22.1. I reverted back to the previous build that did not have this error, but while still using 4.22.1 and now it’s showing this error. This appears to be a problem with 4.22.1.

3

I can confirm. This is a 4.22.1 issue. Packaged the same exact built in 4.22.0 and there is no issue. I’ll submit a ticket for this.

edit -

So, the problem exists with 4.22.0, but it’s much, much more minimal and hardly noticeable. I can’t record a video to show the difference at the moment, but I will once we’re done with our event.

It seems that 4.22.1 greatly exaggerated this issue.

4

Can you give this CVar a try?

5

That actually helps out quite a bit. Most of the effect is gone on the ship. Only a slight effect on a small area of the ship now, but I can further test. Thanks for the suggestion!