how to use SOP att to control POP emission

[sebkaine]

I am banging my head against the wall since yesterday to solve a simple POP problem ...

Basically i am trying to understand how we can control precisly POP emission.

- i have 4 point in SOP

- i have set a frame point att manually (with a dirty expression that i am not proud of ... )

- i have set a emit point att manually

I want to use this SOP to control my POP emission so basically :

- i want each point to emit at the frame define in my frameAtt ,

- and i want to emit a number of particle define in the emitAtt

Unfortunatly after many hours of test with some very exotic expression , i'm still stuck !

so any help would be wonderful .

Cheers

E

test_emit_with_SOP_attr.hipnc

[Peter Quint]

You need to control the geometry going in to your popnetwork node, rather than trying to do it in the source pop. So first off delete (SOP blast) any ponts not due to emit that frame (use an expression of the kind $FF < $EMITFRAME && $FF + 1 > $EMTFRAME - assuming emitframe is the frame attribute). You can them simply emit a particle for each incoming geometry point (use impulse emission with $NPT as the particle count).

Controlling the number of particles emitted per source particle is slighty harder. You could probably duplicate up the incoming points using a foreach sop, or use groups and a split sop in pops.

[sebkaine]

Many Thanks for your help Peter !

I have now a working solution with 99% SOP nodes.

I do find this solution quite geeky and not very straightforward , i post it just in case it could help someone in front of the same pb.

But i would like to know if someone would have a more elegant-simple way to achieve this , by simply transfering att from SOP to POP.

Thanks again for your support !

Cheers

E

test_emit_with_SOP_attr_OK.hipnc

Edited April 22, 2013 by sebkaine