GPUSim Niagara Particles Not Displaying In Packaged Project

Development Asset Creation FX
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Hey guys, I’m having a problem with Niagara GPUSim particles. Originally, we were using hard pointers to all of our particle system references - however we came up on the assertion error that happens on line 55 of the Niagara shader module. Reference: https://answers.unrealengine.com/questions/953089/niagara-shader-module-delegate-never-set.html

We were able to get around that - by deferring the loading of our GPUSIM particles by changing all the references from hard pointers to soft object references. However, while this works perfectly fine in the editor and seems to be getting the correct files during runtime of the build (tested via DebugGame) - the particle system does not seem to display while playing the packaged build.

Switching the particles to CPUSim lets them work and display as we expect. Why would the particle systems be working in the editor and not in our packaged build, and only when they are set to be GPUSim?

We have 6 particles that have this problem, and their implementation varies from C++ to Blueprint, so it doesn’t appear to be an implementation issue as both methods of spawning GPUSim particles are affected. And if we switch everything to CPUSim, the soft object reference seem to be working in build as well so – I don’t believe it is an issue with our code.

Can anybody help out with this problem?

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I have the same problem.

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So I tried figuring out what the problem was.

I managed to focus the issue down to the material that I was using for my Niagara Emitter’s Mesh Renderer. The material that I made used a particle color node which fed into the emissive color of the material.

348651-screenshot-2021-09-14-170900.png
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If I instead decided to use a Constant4Vector in replacement of the particle color, the particle would properly display in build.

348652-screenshot-2021-09-14-171004.png

The issue doesn’t seem to persist if the Niagara Emitter uses a Sprite Renderer but I’m not fully sure about that statement.
Not sure if your issue comes from the same place as mine did but nonetheless, here you go.

1 Like
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This was my problem as well. Upon further testing it wasn’t all 6 Niagara Particles affected and the ones that were - had the same problem with the mesh renderer.

Thank you for the solution!