Shadows flicker frame to frame in parts of a scene (probably RT sun shadows) #572

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opened 2026-10-08 23:53:37 +00:00 by sky_line · 0 comments

sky_line commented

2026-10-08 23:53:37 +00:00

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A user reported shadows flickering in their region. They probably have ray-traced sun shadows on (not confirmed). No in-viewer report has been filed yet; this ticket tracks it until one is.

Symptom

Two frames of the same scene, about one frame apart (attached).
In frame 1, the asphalt at the back is in shadow.
In frame 2, the back is unshadowed, and a jagged dark patch appears at the front (by the hedge and curb).
It flickers continuously.
These are large blocks of shadow switching on and off between frames, not fine per-pixel speckle. That points at the shadow caster set, the cache (cached cascades and the #564 dynamic overlay) or RT instance/TLAS state, rather than the depth bias.

Unknown

Viewer version (Beta 5 has #555 camera-relative and #564 shadow caching; #441 projector acne is not yet released).
Shadow mode: RT or shadow maps, for sun and projectors.
TAA on or off; region name.

Next

Ask for a Help > Report Bug report taken while it flickers.
A/B: RT vs shadow-map sun shadows, and TAA on/off.
Try to reproduce in the region.

A user reported shadows flickering in their region. They probably have ray-traced sun shadows on (not confirmed). No in-viewer report has been filed yet; this ticket tracks it until one is. **Symptom** - Two frames of the same scene, about one frame apart (attached). - In frame 1, the asphalt at the back is in shadow. - In frame 2, the back is unshadowed, and a jagged dark patch appears at the front (by the hedge and curb). - It flickers continuously. - These are large blocks of shadow switching on and off between frames, not fine per-pixel speckle. That points at the shadow caster set, the cache (cached cascades and the #564 dynamic overlay) or RT instance/TLAS state, rather than the depth bias. **Unknown** - Viewer version (Beta 5 has #555 camera-relative and #564 shadow caching; #441 projector acne is not yet released). - Shadow mode: RT or shadow maps, for sun and projectors. - TAA on or off; region name. **Next** - Ask for a Help > Report Bug report taken while it flickers. - A/B: RT vs shadow-map sun shadows, and TAA on/off. - Try to reproduce in the region.

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