Disappearing Particles

Ok,it seems that this is a known issue,and it happened to cross it as well. I have a particle system that when i put it into my scene and play my lvl, the particle was invisible. Suddenly,after some work into my scene(mostly setting meshes in my scene) the particle disappeared. When i am in edit mode,it works fine. Yes i have checked if the actor is not hidden during play, the visibility is on,everything is checked and yet I lost it. Anyone might knows whats going on?

Bounding box size in the particle, or perhaps you have an LOD that’s not spawning anything


Q: Does the Angle you view the particle at, make any difference…?
Is it possible to do a 360 with the Camera in-game to check this…?

The particle is a thunder. It is on the right side.My issue is that the problem appeared suddenly.When I put it in my scene and played it for the first time,it was working.Suddenly I can only see it when I am in editor mode.I didnt change anything that has to do with postproccess, environmental fog. It just stopped working in play mode. I have some issues with the project folder at the moment and I have to update the whole project.So maybe it might fix.But if anyone else has something to suggest,please do so.

I still have the issue.I tested the particle in an empty scene and it works.So it doesnt work only in the particular scene that i am working with.

Ok guys,the issue has been solved.I dont know if this makes a sense to you,but the particle needed a static mesh to detect the surface that the lighting bolt will hit.I dont know if it is possible to make a particle to detect a surface though.I havent seen it before.

if you’re using collision module to spawn, that could be a root cause. It has nothing to ‘hit’ therefore no spawning happens.

@whooosh I had no idea that particles have that kind of attribute.Unreal surprises you all the time :smiley:

Glad you got it sorted!

I mentioned angles before because since 4.15 / 4.16, FX-particles attached to a ship-mesh become occluded / disappear at certain angles. There’s no clear pattern to it. Tweaking 2-sided materials / Bounds settings doesn’t help. And as long as the ship stays ‘moving’, the problem appears to go away. It didn’t happen between 4.8 - 4.14. so something is different in the engine… If the same Particles are placed in the level at design time, they work fine from all angles, same goes for PIE etc…

Any ideas about this @whooosh ???

My first inclination is LODs, try to delete your LODs inside the particle system and re-generate them. I don’t have a solid repro, but sometimes LODs no longer work when engine versions change. Another thing could be some INI is dictating LOD settings, weather it’s distance based or some other optimization that was introduced. Could be a more aggressive global LOD was introduced.

Hello! I fixed my disappearing particles with setting up the color. I’ve used UserParameter which overrides color set in Scale Color under Particle Update, and when I added default values in NS → System Settings → User Parameters, it started to render both in NS and in the scene.