Temporal blur artifacts on Geometry Cache Components in Blueprint actor

Development Rendering
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1

We are currently switching from Skeletal Mesh to Geometry Cache based animations for non-rigid bodies. These assets are part of a rather complex scene structure inside a Blueprint Actor. We are seeing blurry temporal artifacts that look like some sort of motion blur:

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We have already identified that rotation transforms used on either the Blueprint Actor or the Component inside the actor lead to those artifacts. Setting either one to “0” will remove these artifacts:

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We have also tested different AA modes. It looks like this issue appears with TSR only. Disabling motion vectors on asset import or changing any of the Geometry Cache Components properties didn’t change anything.

The issue is visible in UE5.5 and 5.7

Are we looking at a bug here or is there any property or cvar that we can use to get rid of this issue?

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2

Steps to Reproduce

  • Open attached simplified project inside “TemporalBlurArtifacts.zip”
  • Open Level “GeometryCacheSample”
  • Set cvar “r.SetNearClipPlane” to “1” and zoom closer to the geometry

--> see blurring on component “4N4_Rollo_rearXL”

  • Change rotation value of actor “FbxScene_sample” to “45” or “0”

--> no blurring

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3

Hello,

Thank you for reaching out.

I’ve been assigned this issue, and we will be looking into this blurring for you.

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4

Hello,

Thank you for reporting this. I can confirm this issue can be reproduced as described in the latest CL, and have opened a bug report:

The tracker will be visible after it is approved internally at Epic Games and is publicly accessible.

If you have any further questions, please let us know.

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