GPU Particles are causing artifacts in some Debug View Modes

Development Rendering
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1

Hello support!

We recently noticed some strange artifacts on some of our Niagara GPU particles showing up when using some different debug viewmodes (shader complexity, quad overdraw and also wireframe). The bug is quite easy to reproduce on our side so with the Steps above, you should be able to repro it too. If it’s not the case, please let us know and we will provide a packaged project.

I attached a video showing how I can repro the issue as well as two screenshots showing the strange artifacts happening in the Shader Complexity as well as in the Quad Overdraw debug view modes.

Please let us know if you need more information. Thanks!

PS: Not 100% sure but it seems like the issue could be related to the Wind Force Module.

PS2: Using CPU particles would fix the issue.

2

Steps to Reproduce
In Unreal Version: 5.5.3-39772772+++UE5+Release-5.5 in a blank project:

  1. Create a Basic Level
  2. Open Content Browser or Content Drawer (ctl + spacebar)
  3. Right Click and Create a New Niagara System (Choose Blowing Particles preset)
  4. Drag and drop the new system into your Basic Level
  5. Ctl+E to edit the system
  6. Change the Spawnrate from 15 to 500
  7. Set the Viewport to Optimization Viewmodes/Shader Complexity (alt+F8)
  8. You should see some strange behavior
3

Hi Gabriel,

Thanks for the report.

This is related to how we try and use ‘this frames’ rendering results when the sim runs in post render opaque.

I’ll just have to disable that feature when debug view modes are enabled.

Thanks,

Stu

4

Amazing! Thanks for the quick response. :+1: Is it something that could be squeezed for 5.6 or it’s too late?

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Code was submitted into Dev 5.6 branch in CL 42347118, so yes should be in 5.6 :slight_smile:

Thanks,

Stu

6

Amazing thanks for the update! Have a great end of day! :+1: