GPU spawn event removes set particle index in Intialize block - how to achieve effect differently?

Hiya,

I'm sure I'm misunderstanding how this works, but wondering if anyone could explain?

I've got a particle system made with the VFX graph (from Keijiro Takahashi's github).






I would like the location of these particles to be spawned from the positions of another particle system (which is reading a texture map input).

I have done that by using a gpu event, and inheriting the spawn position - but when initialising from a gpu event, the set particle index parameter disappears.





The problem I've got is that this means the particles aren't being drawn in, and there is also only 1 line with a quad at each end, rather than the original which has 2 or 3 connected lines.

I don't quite understand how the strip index is causing this behaviour - but I was wondering if anyone could shed some light onto how I could spawn the first particle system from the location of another set of particles?

Thanks,
Laurien