Hey,
when using krakatoa birth/update on a PRT file. Do you have to save out the Age/ Life span channels? For some reason delete operators aren’t working on my Pflows based on this method, even when they are in same event as the krakatoa birth/update operator.
As explained in the documentation, the deleting of particles loaded via the PRT Birth/Update is performed via the dedicated Krakatoa FileID Test.
When a particle is born in PFlow via the PRT Birth, its ID channel from the file is stored in a private FileID channel.
When the PRT Update refreshes the particles on the next frame, it compares the FileID channel of existing particles with the ID channel of incoming particles from the current PRT frame.
If a particle is in the PFlow system but NOT in the current PRT file, it most probably was deleted in the original simulation. So the PRT Update operator sets its FileID channel to -1, thus flagging the particle for deletion. But you have to put a Krakatoa FileID Test in the flow and send particles with a FileID < 0 to a Delete event to actually get rid of them.
The reason we went with 3 operators is that you can perform the birth on one place, the update in any number of events, and the test can be enabled optionally to delete the particles, or send them to another event without deleting etc. for total flexibility of the setup. In fact, you can send out particles by ANY range of FileIDs, not just negative ones…