Why doesn't my GPUEvent attribute reach the receiver emitter?

GPUEvent passes attributes only when both ends declare them. Send block sets Source Attribute (e.g. Position); receiver's Init context uses Inherit Source Attribute on the same name.

Difference between GPUEvent and CPUEvent?

GPUEvent runs on GPU between particle stages with no CPU readback. CPUEvent goes through CPU and is slower; useful when you need C# to react. GPUEvent is the right tool for cascaded effects.

Can I pass custom attributes?

Yes — declare a Custom Attribute in Blackboard. Send via Set Attribute on the source emitter; Inherit on the receiver. Both names must match exactly.

Fix: VFX Graph GPUEvent Attribute Not Passed

Quick answer: Send block: Source Attribute = Position. Receiver Init: Inherit Source Attribute Position with non-zero blend.

Sparks emitter sends a GPUEvent on death. Smoke emitter spawns at world origin instead of the spark’s position. Position attribute wasn’t set on the send.

The Fix

Sparks emitter:
  Particle Update:
    + Trigger Event Always (or on death):
        Set Position from Self
  Output: GPUEvent (Send)
    Source Attribute: Position

Smoke emitter:
  Init:
    + Inherit Source Position (1.0)   // from Sparks event
    + Set Lifetime, Velocity etc.

Send writes the source attribute to the event payload. Inherit pulls it into the receiver’s init. Custom attributes work the same way.

Verifying

Spark dies; smoke spawns at the spark’s last position. Without Inherit: smoke spawns at receiver’s origin.

“Send sets. Receiver inherits. Cascade aligns.”

Related Issues

For VFX strip collapse, see strip. For spawn over distance, see distance.

Set source. Inherit. Cascade aligns.