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In Progress

Won't Fix in 2023.2.X

Under Consideration for 2022.3.X

Votes

10

Found in

2022.3.19f1

2023.2.10f1

2023.3.0b7

6000.0.0b11

Issue ID

UUM-63692

Regression

No

Motion Vectors bleed through any Geometry when using URP Temporal Anti-Aliasing

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How to reproduce:
1. Open the “MotionVectorArtefacts.zip” project
2. Open the “SampleScene“
3. Enter the Play Mode
4. Observe the Game view

Expected results: Motion vectors do not bleed through the “Wall“ GameObject
Actual results: Motion vectors bleed through the “Wall” GameObject

Reproducible in: 2022.3.19f1, 2023.2.10f1, 2023.3.0b7
Could not test in: 2021.3.35f1 (No TAA)

Reproduced on: Windows 11 Pro (23H2)
Not reproduced on: No other environment tested

Notes:
- The reporter states, that the issue is also reproducible with third-party scripts (DLSS and FSR, both are attached to the project)
- The issue does not reproduce if the “Main Camera” is within around 30 units of the moving GameObject
- The issue is also reproducible in the Player

  1. Resolution Note (2023.2.X):

    Closing as Won't fix due to 2023.2 reaching it's EOL.

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Comments (2)

  1. AlteregoGames01

    Feb 27, 2024 16:20

    Reports say it seems to come from object motion vectors using this Z bias and camera motion vectors not using it.

  2. AlteregoGames01

    Feb 27, 2024 16:17

    BIRP, URP and HDRP all have this issue. BIRP only when Dynamic Batching is enabled, it is fixed when the motionvector depth bias is removed from the following lines:

    BIRP:
    o.pos.z -= _MotionVectorDepthBias * o.pos.w;

    URP:
    output.positionCS.Z -= unity_MotionVectorsParams.z * output.positionCS.w;

    HDRP:
    input.vmesh.positionCS.Z -= unity_MotionVectorsParams.z * input.vmesh.positionCS.w;

    For Unity 2021 URP its also broken when using custom TAA, like FSR 3 or DLSS, so it is highly recommended to backport it to 2021 and 2022 as well.

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