Spawn Prop with VFX in it unreliable?

Development Programming & Scripting
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1

I’m spawning a prop that has a niagara system (auto activate) in it when a cube hits a volume. What’s weird, is that this will sometimes work, but then when I End → Start game it breaks. Also I’ve seen it go from a broken state to a working state by changing function name.

See video - The white dot is the particle effect - First cube works as expected, then I restart the game and the particle effect no longer appears. Dropbox

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/Diagnostics }
using { /UnrealEngine.com/Temporary/SpatialMath }

DetectionDevice := class(creative_device):

    @editable VolumeRefT1 : volume_device = volume_device{}
    @editable VolumeRefT2 : volume_device = volume_device{}
    @editable DeathNiagraFX : creative_prop_asset = DefaultCreativePropAsset

    OnBegin<override>()<suspends>:void=
        VolumeRefT1.PropEnterEvent.Subscribe(OverlapEventT1)
        VolumeRefT2.PropEnterEvent.Subscribe(OverlapEventT2)

    OverlapEventT1(NameOfWhatImPassingIn : creative_prop):void=
        Print("T1 GOAL")
        MyVFXFunction(NameOfWhatImPassingIn)
        #Changed to use spawn when using Sleep in 'Reset Prop'
        #spawn{ResetProp(NameOfWhatImPassingIn)}
        ResetProp(NameOfWhatImPassingIn)
    
    OverlapEventT2(NameOfWhatImPassingIn : creative_prop):void=
        Print("T2 GOAL")        
        MyVFXFunction(NameOfWhatImPassingIn)
        
        #spawn{ResetProp(NameOfWhatImPassingIn)}
        ResetProp(NameOfWhatImPassingIn)


    MyVFXFunction(PassedProp : creative_prop):void=
        Print("MY VFX FUNCTION CALLED") 
        (PropTrans := PassedProp.GetTransform())
            SpawnedPropResult := SpawnProp(DeathNiagraFX, PropTrans.Translation, PropTrans.Rotation)
                #Print("spawned NiagraFX") 
                if (SpawnedProp := SpawnedPropResult(0)?):
                    Print("spawnedProp")

                    #the source of my problems?!
                    spawn{DeathNiagraFXHandleWat3(SpawnedProp)}
                    #Had it written like this before
                    #spawn:
                        #DeathNiagraFXHandleWat3(SpawnedProp) 
                                      

    ResetProp(NameOfPassTwo : creative_prop):void=

        #if (NameOfPassTwo.TeleportTo[vector3{X:=0.0,Y:=0.0,Z:=10400.0}, NameOfPassTwo.GetTransform().Rotation]) {}
       
        #Sleep(3.0)

        #was 4000
        if (NameOfPassTwo.TeleportTo[vector3{X:=0.0,Y:=0.0,Z:=400.0}, NameOfPassTwo.GetTransform().Rotation]) {}

#CHANGING THE FUNCTION NAME MADE PARTICLES WORK AGAIN WAT WAT WAT

    DeathNiagraFXHandleWat3(NiagraFXProp : creative_prop)<suspends>:void=   
        Sleep(3.0)
        NiagraFXProp.Dispose()
        Print("despawned niagrafx")

This method of spawning a VFX has worked 100% reliably for me in other projects…

2

It really could just be an engine issue. I have had inconsistencies with spawning VFX even with the VFX Spawner device. I think the main work around is just to teleport the device/prop to itself which seems to sometimes update it and get it to render.

Also sometimes the UEFN playtest is inconsistent, I would try to publish it and delist it and see if it works more consistently. If it doesnt it could just be an issue with physic props or the rendering.

3

The patch notes today had something where attaching other things to a physics prop was a known issue.