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Particles Trails and points id

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Hello everyone,
I am a new Houdini Indie user, so i might have missed the obvious.

I am exporting a particles explosion from Houdini to Unreal.
it works great except for the trail node. It does export the datas ( file is much heavier with trail node) but the trail node is duplicating the particles id ( and probably all the other attributes).

Once I import a cache in Niagara, I only see the particles from the POP and not the one from the trail.
I tried randomizing the id attribute on a static particle system, and the trails points do appear properly.  ( on an animated one it juste pops a random particle every frame).

I was looking for a way to either, give the trails points an id or create a trail directly within my popnet. 
For the second option i basically want to pop a particles every frame with a 1frame life from each points of the simulation... but I cant find how to do that. 

Do you have any leads to what route to take?


thank you!

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If you just want a point following exactly where your POP particles were on the previous frame, you can branch off the cache with a Timeshift set to $F-1 (or whatever frame offset you want) to get the previous frame and simply add a large offset (i.e. more than the total particle count) to the existing @id atribute to make it unique, then merge it back in with the cache.  SOPS re-evaluates from scratch every frame, so when modifying your cache at that level, you need consistent attributes frame-to-frame (like the static @id attribute with a known offset)

For doing it directly in a POP network, check out the POP Replicate node - it allows you to birth secondary particles off your POP particles that will have unique IDs; removing velocity inheritance and adjusting the shape to "Point" should help, but the SOPs method above is the quicker and dirtier solution if that was all you needed.

This is assuming I've understood what you're asking, of course ;) In general, it's always useful to post even a simple .hip file for others to clearly understand and troubleshoot what you're asking about.

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