Getting a particle to stop

Soccerman18

I'm trying to get particles to stop moving after a certain frame. So for example a superspray would emit particles from frame 0 to 30, and then after frame 30 all the particles would stop moving, freeze in air, but still have everything else in the scene moving normally (cameras and such). I heard that this could be done in video post but I haven't had any luck yet. Also tried changing the speed of the particles, using the track editor, no success yet. Any ideas?

FatAssasin

If you're using Max 6 or higher I would strongly suggest using Particle Flow. Then you can use the Stop operator, along with an Age Test, to do what you want.

The Stop operator is not included in PFlow by default, but can be downloaded here: http://www.orbaz.com/products/particle-flow-tools-freebies.html

Soccerman18

Sweet. Haven't worked with particle flow before. Kinda funky. Is there a way to link it to deflectors and forces? Tried just doing the normal bind to space warp but it's not having any affect.
[edit] ok, got it to do forces, still not deflecting though[/edit]

Soccerman18

After playing around for a few hours I got it to work, sorta. It works with forces and deflectors, but I haven't been able to get them to play nicely together. Right now it's hitting the deflector, bouncing a bit, then coming to a stop, but any force I add seems to have no affect. I tried putting the force in both events(one event is looking for the collision and the other is handling the result of the collision), and in each but it still does nothing. Is there something I'm missing?

Also, I've been reading the event stuff like it's code (it even looks like a normal flowchart). Is this correct or do events happen in parallel or in some other way that disregards the linking?

FatAssasin

Post the scene if you can, or a screenshot of pFlow chart and movie of what it's doing.

Soccerman18

Well, I tried redoing it at home this weekend and suddenly it worked. I just tried the file I had here at work and it was the same, but it didn't work. Redid it and it worked. I think something may had been funky with the file.

Not sure I'm going to be able to do what I wanted though. What I'm trying to do is have particles fill up a space defined by deflectors (I have a simple box shape that has no top right now) and then I was going to use a particle bomb to blow it up and have the particles scatter, freeze the particles and move the camera around to focus in on a few of them. But right now the particles aren't filling up the area, they just it the bottom deflector and fall flat. Using blobmesh to try and get the blobbyness but the blob isn't getting bigger as there's more particles.

FatAssasin

If you need particles to take the shape of an object, you can use the Position By Object operator. Make a box, assign that box as the position object, and then change it from surface to volume. I think that might get you closer to what you want, maybe.

Soccerman18

Position object just seems to make the object the emitter, not getting it to be a container for the particles. Sorta got something working, using speed by shape and having it change the speed and acceleration when it's in the box, sort of a work around that's kinda faking what I'm trying to do.

FatAssasin

Did you change the Position Object operator from Surface to Volume like I mentioned? I just did a quick test and works fine.

Soccerman18

Yea, did that. The particles formed within the box and came down as they normally would. The particles were constrained by the box when they're created, but I'm trying to get them to be created outside the box and stay and fill the box when they enter it, like pouring water into a glass.

FatAssasin

Ah, I see. Yeah, that's really hard to do.

Eric Chadwick

Not that hard, if I understand you correctly. Here's a super-simple example, max 8 format. Uses a UDynaFlect deflector, which lets you choose arbitrary geometry. Replace the particle system and you're good to go.
http://www.ericchadwick.com/examples/files/particles_filling_a_box.zip

Soccerman18

Does UDynaFlect work with particle flow? I tried using a collision event but it didn't see the UDynaFlect as one of the possible deflectors. Tried using a UDeflector, seems to see that though.

Is there a way to keep the particles a certain didstance away from each other? Particle flow has a keep away event which adjusts the speed of the particles to keep them apart, but when they're constrained by the box they still just fall flat onto the bottom. If there's a way to force the particles to stay a certain distance from each other and if they're constained by the box, then the only way for them to keep that distance would be to move up, filling the box.

FatAssasin

Sounds like what you really want is particle dynamics, which isn't available yet but should be soon. Take a lot at this video showing what you'll be able to do with pFlow when Oleg gets around to releasing his Box #2 update.

http://www.orbaz.com/animation/BeachBalls.avi

Soccerman18

yea, looks like that'd do it. sucks that I'd have to drop $400 to do it though.

Eric Chadwick

Ah yeah, forgive my lack of understanding. Cool challenge, wish I knew particle flow better. Did you know about Brandon Davis' tuts? Kinda old, but might help, dunno.
http://www.particlefx.com/education/PFlow/

Soccerman18

Did not know about those tuts, they're pretty helpful. I haven't worked with particle flow before, so you probably know more about it than I do. Was looking at making a scipt for it, if I can figure out how to control the location of each particle then I can make it behave the way I want.

Eric Chadwick

Hehe, I doubt it!
Another free resource though...
http://www.scriptspot.com/bobo/mxs5/pflow/

Eric Chadwick

I just had an idea... maybe use Reactor with some spheres to get collisions so they will fill the box, then somehow convert them to blobmeshes, or link blobs to them. Might work.

Also look up "interparticle collision" in the Help. Some ideas there that might work, without Particle Flow.

FatAssasin

That's a good idea. I think that you'll probably have better luck with Reactor.