I am experiencing a TSR ghosting artifact during a Day/Night transition in Sequencer. The issue occurs only while transitioning between the Day and Night sky textures. The Day and Night states are both stable when used individually. Setup: - Unreal Engine 5.8 - TSR - Sequencer - Sky material using two textures blended with a Scalar Parameter - The textures are rotated using RotateAboutAxis / VertexNormalWS - Trees use masked foliage materials Reproduction: 1. Set the sky to the Day texture. 2. Set the sky to the Night texture. 3. Animate the Scalar Parameter from Day to Night in Sequencer. 4. Place masked foliage trees in front of the sky. 5. Play the sequence. Result: Previous-frame sky information remains visible around the masked foliage, producing an alpha/ghosting artifact. Additional tests: - Day only: No artifact. - Night only: No artifact. - Day → Night transition: Artifact occurs. - Sky Pixel Animation OFF: Artifact still occurs. - Placing an opaque black wall behind the trees: Artifact disappears. - Replacing the background with a glass/translucent material: Artifact occurs. - Disconnecting the Lerp Alpha: Artifact disappears. This appears to be related to TSR history/reprojection during a changing sky background behind masked foliage.
Hello there @JamyeongLEE!
Checking with my peers, what could be going on here, is that TSR’s previous frame history is being affected by the day/night transition, as the sky’s color change. So, the previous color from the sky is getting mixed in the process.
One possible fix, is to change the way the material handles background changes. Open your masked material, navigate through its Details panel, and under Translucency > Advanced, look for “Responsive AA” and enable it. This will tell TSR to discard history much faster, preventing the old sky color from affecting your foliage:
Hello, @brs-sebascova!
Thank you very much for taking the time to respond and for suggesting this solution.
I tested the suggested approach on my current level, but unfortunately, it does not seem to be a good fit for my project setup. After applying it, the foliage became noticeably brighter than expected.
The vegetation assets I’m currently using have a variety of material configurations, including Opaque, Masked, and Two-Sided Foliage materials, depending on the asset. As you mentioned, I think there is a high possibility that the issue is related to TSR’s previous frame history.
When I enable Pixel Animation on the sky material, the issue disappears, but the overall flickering becomes significantly worse.
Also, switching from TSR to TAA completely eliminates the issue. Based on these results, I suspect the problem is more related to TSR’s temporal history handling than to a specific foliage material setup.
That said, my goal is to get the project working reliably with TSR rather than switching to TAA, so I’ll need to investigate this further and find a solution that works with my current project setup.