Procedural mesh placement on terrain using line trace downward

Pattern for snapping object to ground: GetActorLocation → Add Vector(Z=+1000) → as TraceStart. GetActorLocation → Subtract Vector(Z=1000) → as TraceEnd. LineTraceByChannel(Start=TraceStart, End=TraceEnd, TraceChannel=Visibility) → Branch(ReturnValue=true) → BreakHitResult → SetActorLocation(NewLocation=ImpactPoint) → SetActorRotation(NewRotation=MakeRotFromZ(Normal)) [align to surface normal]. MakeRotFromZ takes a 'Z' input Vector and outputs Rotator aligned to that normal.

Vertical Box

Lays out children top-to-bottom. Children's Size pins control how space is distributed.

SetWorldLocation on component — set component world position

K2_SetWorldLocation. USceneComponent method.

Spawn actor at location with rotation

Pattern: MakeTransform(Location=SpawnLocation, Rotation=SpawnRotation, Scale=(1,1,1)) → SpawnActorFromClass(Class=ActorClass, SpawnTransform=Transform) → CastTo<YourClass>(ReturnValue). SpawnActorFromClass inputs: 'ActorClass', 'SpawnTransform' (Transform), not separate Location/Rotation. Use MakeTransform node to build the Transform struct from Location+Rotation+Scale.

SpawnSystemAtLocation — spawn Niagara particle system at location

UNiagaraFunctionLibrary::SpawnSystemAtLocation.

SetRelativeLocation on component — set component position relative to parent

K2_SetRelativeLocation. USceneComponent method.

SpawnEmitterAtLocation — spawn particle effect at world location

UGameplayStatics::SpawnEmitterAtLocation. For Niagara, use SpawnSystemAtLocation.

GetComponentLocation — get component world position

Spawn actor at location with collision handling

Pattern: Trigger → SpawnActorFromClass(Class, MakeTransform(Location, Rotation, Scale), CollisionHandling, Owner) → ReturnValue → IsValid branch → use spawned actor. Always check IsValid on ReturnValue. For many spawns, spread across frames with timer to avoid hitches.

Horizontal Box

Lays out children left-to-right. Same Size pin model as Vertical Box.