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particle creep


mic

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hello again, please help me - i want to generate particles on the object and creep them on it surface, and the 'force' to their movement is just gravity.. how can i do this? i think creep POP can help me, but it gives strange results, when i apply it.. thanks!

and the second question after this is how to say them (particles) to creep on the surface by some trajectory, for example noise-like, or sin-wave like..to simulate draining effect!

upd.

oooh sorry everything is explaned even on this page!

http://forums.odforce.net/index.php?showtopic=8462

http://forums.odforce.net/index.php?showtopic=8021

sorry and thank you)

Edited by mic
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hello again, please help me - i want to generate particles on the object and creep them on it surface, and the 'force' to their movement is just gravity.. how can i do this? i think creep POP can help me, but it gives strange results, when i apply it.. thanks!

and the second question after this is how to say them (particles) to creep on the surface by some trajectory, for example noise-like, or sin-wave like..to simulate draining effect!

upd.

oooh sorry everything is explaned even on this page!

http://forums.odforce.net/index.php?showtopic=8462

http://forums.odforce.net/index.php?showtopic=8021

sorry and thank you)

upd2

the only question to Johner's example is - what to do when the objects moves??

more exactly - if object moves and i want to create stains, not the single creeping particles.. and split POP or trail SOP don't stay on the surface..

Edited by mic
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upd2

the only question to Johner's example is - what to do when the objects moves??

more exactly - if object moves and i want to create stains, not the single creeping particles.. and split POP or trail SOP don't stay on the surface..

In your Split POP, make sure that you're inheriting the posprim and posuv attributes from the parent particle (you should be by default), then you'll need another Creep POP to stick those "trail" particles to the surface. Also, you may need to turn up the oversampling of the POP net a little if you've got fast moving geometry.

I've attached an example. The white particles are the original sliding particles, the red ones are the trails.

Birth_Sliding_Particles_trails.hip

Edited by johner
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In your Split POP, make sure that you're inheriting the posprim and posuv attributes from the parent particle (you should be by default), then you'll need another Creep POP to stick those "trail" particles to the surface. Also, you may need to turn up the oversampling of the POP net a little if you've got fast moving geometry.

I've attached an example. The white particles are the original sliding particles, the red ones are the trails.

thank you very much Johner! that's it!

the question is.. why it is so slow?.. even if only one particle, oversampling = 2.. very slow calculations - creep POP is very complex? or what is it?..

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thank you very much Johner! that's it!

the question is.. why it is so slow?.. even if only one particle, oversampling = 2.. very slow calculations - creep POP is very complex? or what is it?..

Yes, I think it's the Creep POP. It could have to do with the complexity of the input mesh that the particles are creeping along. I bumped up the complexity of the sphere so that the mountain SOP would be more smooth. You could try disabling that and decreasing the sphere complexity to see how things speed up.

By the way, the Performance Monitor window is a great tool, especially with the new "Highlight > " option. Open it, choose the menu item that say "Cook only" and then set it to hightlight all operations over 10 ms or so. You should see the Creep POP show up.

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Yes, I think it's the Creep POP. It could have to do with the complexity of the input mesh that the particles are creeping along. I bumped up the complexity of the sphere so that the mountain SOP would be more smooth. You could try disabling that and decreasing the sphere complexity to see how things speed up.

By the way, the Performance Monitor window is a great tool, especially with the new "Highlight > " option. Open it, choose the menu item that say "Cook only" and then set it to hightlight all operations over 10 ms or so. You should see the Creep POP show up.

thank you, Johner!

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