[Sidefx-houdini-list] Trim the end in chop when point is not there anymore

Francois Duchesneau sidefx at trinix.ca
Mon Dec 15 18:14:38 EST 2008

Unfortunately I cannot do that because my particle system has 800000
points and I need to compute the nearestdist attribute.

At some point in my simulation, particles get very close and this make the
calculation of nearest dist very heavy. Since it gives me trouble anyway
when I render because of a huge depth of opacity then I've got to get rid
of them :(

However I've found a way. I create an attribute that holds the current
frame and I query that in chop with the icmax. This gives me the last
frame just before it dies. After that I query the last position in xyz and
set it constant for until the end. That way the filter works fine.

Now I started it that but guess what, chop doesn't seem to like to compute
800000 times my expressions and all. I'm going to try what Georg
suggested. Maybe it'll be lighter.

Thanks everybody


> This is a good habit to get into regardless for deformation blur purposes.
> G
> ----- Original Message ----
> From: Andrew D Lyons <tstexture at gmail.com>
> Best workaround - Birth all at start and don't have them die - so you
> get constant point count over frame range (be sure to store actual
> desired birth and death frames on the points.). Filter in CHOPs, and
> afterwards animate visibility using stored birth + death so they
> appear to birth and die at correct frame.
> 2008/12/15 Francois Duchesneau <sidefx at trinix.ca>:
>> How can I set the end of the sampling per point instead of a constant
>> value for all of them? The main reason is because it gives me a bad
>> filtering.
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