[question] point travel on the surface

[pybada79]

hi everyone

i have some questionsso i try to get the hint at this forum

i want to make that some particle travel on the geomety surface

like this

http://vimeo.com/4291779

i had tried use creep sop and creep pop but there have some problem the problem is i cant control the birh location and particles are gathered at end of UV

so i want to ur answers

anybody got some idea?........and im so sorry my bad english.........^^;;

[michael]

maybe try the ray sop?

[Jason]

maybe try the ray sop?

Particle slide maybe too?

[pybada79]

Particle slide maybe too?

yup i had test creep pop slide type but i feel less diffrence.

and its also difficult to moving around the surface because it just use UV so i feel hard to make various moving

im ray sop testing now m.......

its not easy particle move around looks like sphere .

[edward]

I thought Jason was talking about Collision POP sliding?

[Jason]

I thought Jason was talking about Collision POP sliding?

Thanks Edward, yes I was. Unfortunately there is no way to birth a birth in a collided state (either STUCK or SLIDE states, or whatever;RFE'd for years coz it's a real pain in production) which makes the first timestep really tricky to get exactly right, but it's worth checking out, maybe.

[brianburke]

Another approach is perhaps getting an SDF volume from your geometry and moving your velocity about the cross product of the gradient of the volume. This gives very uniform looking results, so to add some variation, you could use the gradient of the volume as the axis for a noizee driven quaternion rotation. This has some issues with sinks and patterns appearing, but it might be tweaked to work better than the slide/creep behavior.

Just a thought.

flowparticles.hip

Edit: oh, i forgot to add in the file - we can easily prevent the particles from slipping away from the surface by using the gradient and sample to measure the distance from and direction to the surface and adding that to velocity.

flowparticlesresolovedistance.hip

Edited May 24, 2009 by brianburke

[pybada79]

Another approach is perhaps getting an SDF volume from your geometry and moving your velocity about the cross product of the gradient of the volume. This gives very uniform looking results, so to add some variation, you could use the gradient of the volume as the axis for a noizee driven quaternion rotation. This has some issues with sinks and patterns appearing, but it might be tweaked to work better than the slide/creep behavior.

Just a thought.

flowparticles.hip

Edit: oh, i forgot to add in the file - we can easily prevent the particles from slipping away from the surface by using the gradient and sample to measure the distance from and direction to the surface and adding that to velocity.

flowparticlesresolovedistance.hip

wow!! oh~ thanks to brianburke

ur file is so great helpful for me

i have not fully understanding at vops but it seems look so good idea.

thanks ^^