CopySop with POPs. Triggering animation when the particle collides&#33

[Akabane]

Hi there, i'm having a little fun with pop and copystamping.

I have a mesh not-animated and copied it into a POP network with colliding particles. I want to make a simple animation of it, but trigger it only when the template particle collides. Any tips on how to make it?

I thought i should use the Timeshift SOP and trigger it with an "if" statement based on, say, pstate (since it changes when particle has JUST collided and when it stops, which is my case, the particle stops after colliding). But i don't know then which time variable to use, since all of those are pop-independent ($F, $T) or only pop age dependent ($AGE, $LIFE).

Then i thought i could create a custom attributes thats created as 0 and, from when the particle collides, gradually increase it, then use it to drive the TimeShift; but also in this case, i don't know where to bang my head on.

Any headlights?

Thanks!

[anim]

you can add "hittime" attribute in Collision POP

then use that information to offset animation in Timeshift SOP

to be able to use $HITTIME variable in Copy SOP you need to add Attribute Create SOP after POP Network (point attribute "hittime", variable "HITTIME") and uncheck Write Values

then create stamp variable

something like $T-$HITTIME

of if($HITTIME==-1, 0, $T-$HITTIME)

then stamp this in Timeshift SOP in Time parameter (Method: By Time)

[Akabane]

Clever, right. Thanks a lot, didn't think of using hittime subtracting it from time, wow.

Kudos!

EDIT: BTW, is creating a new attr out of pops a good way to make some attrs (like also PSTATE or such) accessible in the copysop? Thanks again!

Edited May 4, 2010 by Akabane

[anim]

i am using it all the time, I have not tested speed comparing to point() expression however

i am also used to append attribute SOP and delete all attributes i won't need then cache particle sequence to disk

then bring it back with File SOP and then Copy SOP or whatever

[Anatol]

Thanks a lot!

Edited March 1, 2015 by Anatol