Pop's inherit velocities

[tony]

Hi,

 

I've got a scene with some particles inheriting their velocities from sops. I can't seem to get the particles to match positions with a duplicate set of points which have just been displaced along the sop velocities. What am I missing?

 

(Please find my scene attached - created in Houdini 13.0.288)

 

Cheers,

 

Tony

pops_velocities_test.hip

[danw]

Under the POP Source node, Birth tab, you have Jitter Birth Time set to Positive... that will spread the birth of the particles throughout the first timestep, rather than birth them all at exactly the same moment, so they all get offset by a percentage of their velocity that frame, rather than the entire velocity.  Turn it to None, and your particles will move to the positions you're expecting by the start of frame 2.

[tony]

That looks a heck of a lot closer! Thank you :-)

 

Just being pedantic now, but why does it still not match exactly?

 

Cheers,

 

Tony

[danw]

Erm, not entirely sure why, but set the POP Source>Source>Emission Type to All Points, instead of just Points.  For some reason, impulse-emitting 7000 particles isn't necessarily emitting 1 particle per input point, All Points pretty much just copies the input points directly as particles, you only need to control it with Activation then.

[tony]

Cool, thank you :-)