Niagara collision problem: particle collision result seems use other particle's

[ohunry]

reproduct steps:

1. Modify engine souce code, then compile
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
2. open “CollisionQueryAndResponse”
   
   
3. find “Perform Collision Query Async CPU” node, delete it, and create a new one:
   
   
4. create a Niagara System:
   
   
   
   
   
5. change “Loop Behavior” to “Infinite”
   
   
6. Add “Collision” (keep default is ok):
   
   
7. Drag the system to level, check the Output Log window:
   

The reason why I found this problem was I made a falling leaves effect, I stop leaf movement when it hit something, but sometimes they stop on the sky, very strange, can you help?

[Michael.Galetzka (MGaletzka)]

Thanks for the report, we’ll look into it. What engine version did you use for this, 4.27 or UE5?

[ohunry]

I test on 4.27 and UE5, both have the problem

[Michael.Galetzka (MGaletzka)]

This should be fixed in Hotfix 5.0.2.

If you need a workaround for 4.27, either backport the fix or disable interpolated spawning and set the default value of the collision module’s query ID to -1.

[LinkRealities]

Do you maybe have the Rev. for that fix from the Hotfix 5.0.2.?

[Michael.Galetzka (MGaletzka)]

Yeah, fix is in CL 19941008: https://github.com/EpicGames/UnrealEngine/commit/67053ace207240e6b82e8dce8cd9725d97291be1