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Particles - splitting breaks my gravity and collision?


chrsmith

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Hi Particle Masters,

I'm trying to make a water spout and am getting some weird things happening that I don't understand. I've simplified my work to only three particles for study. I'm having the particles split so that they're like droplets with trails behind them. Gravity and collision don't seem to be working when the split is involved.

I've attached my simple example.water_spout_simple_example.hip

With the POP order the way it is, it works the way I want, except the collision doesn't work properly. Either the split particles or the original particles are no longer colliding, I can't tell which.

If I connect the gravity (Force POP) so that it's after the drag and before the collision, then the collision works, but the gravity isn't working properly.

If I re-wire it so that the split and drag POPS are out of the chain (simply bypassing doesn't work properly, they need to be unhooked for collision to work), then both gravity and collision works properly.

Anyone have any tips?

Christine

Northrop Grumman

Engineering Visualization Resource

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You can think of the split as a brand new particle system, this enables you to apply totally different rules and forces to the split particles without being tied to what you've done to the parents. You'll notice that the wire running into the split is a dashed line rather than solid, which denotes that you are feeding data into a separate geometry stream. You can use a collect to fold them back into the same stream, and groups to differentiate between parent and split particles, or you can just duplicate the nodes you want to use in each stream.

water_spout_02.hip

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Thanks guys!

Ehsan, it looks like it worked, until after frame 21, the particles started falling through the collision object. I don't know if you had the same result?

tjeeds, I had some errors opening yours and had to re-wire, but it works. Thanks for the explanation. I had been playing with groups to try to figure out which were the original objects and which were the splits, but I couldn't seem to get them separated. Looks good.

I really appreciate both of your replys, thanks!

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Ehsan, it looks like it worked, until after frame 21, the particles started falling through the collision object. I don't know if you had the same result?

Yes it does, and it's because your birth group (the group with 3 particles in it) keep emitting and since it's already colliding with that grid, and particles are points and have no volume, the new born particles don't see anything to collide and just keep moving down! it can be easily fixed though, but I don't think you need it now :D

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Yes it does, and it's because your birth group (the group with 3 particles in it) keep emitting and since it's already colliding with that grid, and particles are points and have no volume, the new born particles don't see anything to collide and just keep moving down! it can be easily fixed though, but I don't think you need it now :D

Ahh! That makes sense. Thanks!

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