Hi Pierre, thanks for testing.
So if in Popcorn I create a new Simple fx.
Add an Attribute Sampler Shape called Target.
Then for the velocity of the simple effect, in the spawner script I Velocity = Target.samplePosition();
This works in popcorn, no matter where i move the attribute sampler shape, the particles will fly towards it.
Then importing to Unreal, if I move the emitter off 0,0,0 the particles will not hit the attribute sampler shape. https://we.tl/pA3neHpYGM
Here is an example file, import to Unreal, add a Popcorn shape sampler, set that sampler in the emitter settings, then move the emitter off 0,0,0 and the particles will be offset and no longer hit the sampler.
I know this must be something simple, any help much appreciated.