View Full Version : spring constraint reactor rigid body to particles

06 June 2010, 12:43 PM
Hey guys!

I'm trying to simulate debris floating in a flood wave with particle flow and reactor.
This is what I was hoping to get away with:
1. use pflow to move several hundret particles along the water surface, apply push, drag etc.
2. for each particle, spring contrain a rigid body object to it
3. use reactor to sim the collision between all the objects, while the particles keep dragging them forward

However, I have not been able to find a way to attach/constrain reactor objects to particles - and I'm begin to fear that I'm approaching a dead end.

Do you guys know a way to pull the particle-driven-reactor-sim off - or do you have a better approach to the problem? I don't have time/money to buy addons right now, but I don't mind getting my hands dirty with maxscript.


06 June 2010, 06:31 AM
It's pretty much a dead end :D, but I can think of one or two ways to do it -- you can either export your particles to objects, and then attach constraints, or if you feel like trying, you can maybe use a script operator in pfow that controls scene objects, that in turn the rbds are attached to. The reactor preview wouldn't work, but I don't see why it wouldn't work just hitting simulate.

06 June 2010, 10:35 AM
That's almost exactly what I ended up using :D
It's a shame that pflow doesn't come with things like inter-particle collision - without paying hundrets of bucks for addons.
I only need reactor for the collision of the pieces and the whole particle-to-reactor-workflow + simulation is really painfull and slow.

06 June 2010, 02:45 PM
Now I have a new problem - which is not only pflow related: the rigid body objects intersect at the start.
The problem is that the particles in the simulation all use the same keep-apart distance - when I place debris pieces with different sizes, some of them will intersect.

Afaik keep-apart can use the particle's size to scale it's force field - but it still assumes the particle to be a spherical shape, right? So very long objects would still intersect or be too far apart.
Do you know a robust way to resolve reactor object-intersections? (I tried using wind and manually moving them apart so that their spring would pull them to the particle - but at some point reactor would introduce new intersections) Is there a way to 'rattle' on all the rigid bodies of a simulation?

Alternatively I could try to set the particle size according to the debris piece that will be assigned later - but it wouldn't completely resolve the issue, I'm afraid.

CGTalk Moderation
06 June 2010, 02:45 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.