Mesh Particles flicker when GPU Instancing active (Unity's standard Particles Shader)

[DragonCoder]

Hello Community,
am having a strange problem on Windows and with any Unity version (tried 2021+ as well as the newest beta).
Particles flicker heavily as one can see in this video:

https://www.dropbox.com/s/r1dvxe6768byra0/ParticleMeshOclusion - SampleScene - Windows, Mac, Linux - Unity 2021.2.0b3.3078.7 Personal_ DX11 2022-03-04 03-01-45.mp4?dl=0

If I disable GPU instancing: No flickering. Enabling GPU instancing: Flickering.
It only happens when there is more than one type of particles visible and once there is a substantial amount of them.

Am using the normal particles shader there on the built-in rendering pipeline. The regular standard mesh shader does not have this problem but it does not utilize the color channel how I need it.

What I have tried so far to change without any improvement:

• Pressing the “Apply to Systems” button for the “Required Vertex Streams” sections of the materials.
• Particles sorting modes
• Particles render alignment
• Camera- as well as particle- positions and rotations
• Changing camera Rendering path (Forward\Deferred)

Anybody have an idea?
Huge thanks!

[richardkettlewell]

You may have hit this issue: Unity Issue Tracker - Particles flicker when using GPU Instancing
We are investigating what’s causing it.

[DragonCoder]

@richardkettlewell

You may have hit this issue: https://issuetracker.unity3d.com/issues/particles-flicker-when-using-gpu-instancing
We are investigating what’s causing it.

Ah very interesting.
Sorta coincidentally (I merged my work into a briefly older project where I want to use it and the issue disappeared), I have been able to narrow down the Unity version way further!

It happens in:
2021.2.0b3
But NOT in:
2021.1.2f1

Hope that helps to fix it

[DragonCoder]

Yay, can confirm, 2022.1.0b13 fixed the problem thanks to ticket: Unity Issue Tracker - [URP] Particles are flickering when in Play Mode

Thank you, @richardkettlewell and others of the Unity team!