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Under Consideration for 6000.6.X
Votes
5
Found in
6000.0.66f1
6000.4.0b5
6000.5.0a5
6000.6.0a2
Issue ID
UUM-133562
Regression
No
[RenderingDebugger]Motion vectors are displayed when Phong Tessellation is used on the material and Skinned Motion Vectors are enabled on the GameObject's Skinned Mesh Renderer component
How to reproduce:
1. Create a new HDRP Unity Project
2. Import the attached “robot_motion_vector” custom Package
3. Open the “Robot” Scene
4. Navigate to Window > Analysis > Rendering Debugger
5. In the Rendering Debugger window open the Rendering menu
6. Set Fullscreen Debug Mode to MotionVectors
7. Observe the Game view
Actual result: Motion vectors are displayed
Expected result: No Motion vectors are displayed
Reproducible with: 2023.1.0a1, 6000.0.66f1, 6000.3.6f1, 6000.4.0b5, 6000.5.0a5
Reproducible on: Windows 10 (by user), Windows 11
Not reproducible on: No other environments tested
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SunnySunshine
Feb 13, 2026 13:01
I really wish this can be solved. There's a tremendous amount of jitter and ghosting when using phong tessellation on skinned meshes with alpha dithering (while using temporal AA and/or dynamic resolution with DLSS or FSR). This is due to the incorrect motion vectors being rendered.
When doing the phong offset, only the vertex seems to be offset, but not the data from the previous frame. This means that there will always be a difference between those two vectors (current vertex and previous vertex), even on stationary objects, causing perpetual motion and jitter.
A solution would be to offset the previous vertex the same way the current vertex is offset.