Unreal Engine Issues

Crash when setting Kill Particles to true on some emitters in a Niagara System

When setting the Kill Particles boolean of an emitter in a Niagara System to true, the editor crashes. So far, I've only been able to reproduce the issue with the NS_EH_KP system that a user provide ...

Crash when adding an Event Write node to a Niagara Scratch Pad module

It seems that the crash is related to all of the "Write" events. I tested the Event ChaosDestruction Write, Event Float Write, and Event Bool Write and all 3 caused the crash, but their "Read" count ...

SceneCapture2d affects Niagara GPU particles with translucency sorting enabled

The issue comes from sorting being abled while having a scene capture actor. The enclosed 7z contains assets relevant to reproducing the issue. ...

Sphere Trace Distance Field GPU function hides necessary Collision DI input

The collision DI input is a hidden input, but is necessary for compilation. The input node should likely be marked as required, not hidden.  ...

Managed particle systems can fail to be removed from managed ticking when pending registration

UParticleSystemComponent::SetComponentTickEnabled can fail to disable ticking due to IsTickedManaged not checking if the particles system is pending registration. The crash was in part because of c ...

A use-after-free issue caused by GPUParticle

Niagara Component can crash if ticked with a null tick function

Niagara components don't null check their tick functions, and can cause a crash as a result. Compare to UParticleSystemComponent::TickComponent which does. It's fairly common in the engine to pass n ...

Precompile occurs in Niagara when Standalone is started, increasing load time.

In 4.26.1, if you remove the collision module from NiagaraSystem, the Precompile will not occur. ...

Pasting an Emitter In Niagara System is not created at cursor position

Not a regression as this also occurs in //UE4/Release-4.25.4 Behavior should work like other BP nodes, where copy/pasting puts the node where the mouse cursor is located. Current behavior is time ...

Fountain emitters are constantly showing errors in the timeline and are not displaying correctly

This issue is not present in 4.25.4 You can also avoid the problem if the LoopBehavior of the EmitterState is Multiple and LoopDelay is enabled. [Image Removed] It seems to be a binding of certai ...