Parting particles around an object

[woodenduck]

Good day people,

I have a particularly perturbing particle problem.

I have a cloud of particles moving through a scene. I want these particles to encounter a static object and flow around it, but then reform in to their original shape on the other side of the static object and continue on their way. Similar to the way water would flow around a rock in a river.

Any suggestions welcome,

Thanks guys!

[kustaa]

hey,

i gave it a go with sdfs and voppops.

first im checking the TX TY TZ from source points and using those as goal values on voppop.

in the same voppop i push the particles away from the blocking geo(sdf).

the sdf force could be improved a lot but maybe it gives u a starting point.

Kustaa

goalparts.hipnc

[woodenduck]

Hey,

Thanks Kustaa, I don't have much experience with voppops, now is a good to learn I guess!

It looks pretty awesome, thanks for your help.

Joe

[woodenduck]

Hi Kustaa,

Do you know how this might be adapted to work with deforming geometry? If the particles were generated from a walking character, so that the character would appear to flow through and around the static object?

[kustaa]

Hi Kustaa,

Do you know how this might be adapted to work with deforming geometry? If the particles were generated from a walking character, so that the character would appear to flow through and around the static object?

hi Joe,

i didnt know if you wanted to have volumetric goals inside your deforming mesh or just the surface. so i chose the more intresting challenge =)

attached there is a volumetric goal setup.

i start from the source geo(non deformed).

-on one stream(goal) i store restPosition for each surface vertex.. deform.. scatter points to volume.. transfer the restP from surface vertices to volume scattered points(i used a pointcloud in vop approach for sake of speed. it would be more precise with attrTransferNode but its also quite much slower).

- on the other stream(particles) i scatter points to volume, store restP, emit particles once from each point, in vopPop i use pointcloud(the goal points) to look up the worldPosition based on the restP. from that i calculate the force. theres also goalOffset attribute on each particle so that each particle dont follow exactly the goal point.

with this approach you can have different number of points on goalPoints and particles. you should keep the isoOffset rez in goal points fairly low cos it needs to be calculated for each deformed frame. and also you can keep the amount of goal points fairly low to keep the pc calculations fast.

right now theres no force for the surface avoidance that i had in my previous setup. but ill post an update for that force aswell once i get back to my other desk.

Kustaa

volumeGoal.hipnc

Edited July 31, 2010 by kustaa

[hound007]

Kustaa,

It looks fantastic!! Thanks for sharing!