Collision & Gravity Issue

[neuromancer1978]

Maybe post your scene file. I do dynamic sims, and this sounds easy but I would have to see it for myself. As long as you have Maya 6.0.1.

[RaGzMaN]

perhaps try upping the geo con' tessalation factor

[BadG3r]

perhaps try upping the geo con' tessalation factor

nope tried it, but it didn't work neither.

I work in m7. So here's the scene file.


Greetings

[neuromancer1978]

I have no idea. I also tried to open the file and as I suspected it would not.

I would say to check everything. It also depends on the geometry, if you use NURBS that might affect it differently as opposed to Poly.

[Meald]

BadG3r, I opened your scene, applied gravity field to particle2 object, then connected it to floorShape in Dynamic Relationships editor (it was not connected) and they started to bounce off the floor alright...
But when I connected particle2 to the existing gravity field the particles started to fall through the floor. The thing is the magnitude of the gravity field is set way too high (30) and hence the speed of particles was too high for the collisions to be detected correctly. To deal with this situation you need to either decrease the magnitude or increase the number of over samples (2 should be enough) in Solvers->Edit Oversampling or Cache Settings...

[Aikiman]

There's nothing wrong with the mag of your gravity. Increase the inherit factor of particleShape2 to about .6, this will make them bounce in positive y a bit higher then obey your collison on the floor. Maya seems to think that your new particles are lower than the ground plane so by giving them a bit of height seems to fix that. Also make sure you do your connections through the Dynamics Relationship editor.

[Edit] Meald's solution with lowering the gravity may be a solution but then you lose the timing of the particles fall motion.

[BadG3r]

:applause: :applause: :applause: :applause:
thx aikiman (of course, all of you). But still this behaviour is kinda weird to me. But for now I have bouncing particles and that should suffice (for the moment).

Also make sure you do your connections through the Dynamics Relationship editor.

I just reseted the connections between parti2 and gravityfield/floor. I thought the glitch must be somewhere else, cause I connected them correctly. Anyway....

Thx

[Meald]

I can try and explain this behaviour. Please, correct me if I'm wrong.
Collisions are detected at certain moments in time with fixed step. And this time step should not be too large relative to speed of particles (or whatever). I mean if a particle travels too much in one time step and its trajectory intersects collision surface the collision may not be detected.
It was the case with your scene. Gravity field pushed particles too much. Aikiman suggested to increase the inherit factor, i.e. increase initial speed in positive Y-direction which prevented the particles to be pushed right through the surface at the time they were born.
Or as I suggested you could decrease time step (increasing number of ovesamples) so that collisions are forced to be detected more often or just decrease the magnitude of the gravity field so that the particles are not pushed too much downwards.
Hope that makes things clear.

[Aikiman]

Like most things in Maya, there are many ways to skin a cat, consider your cat skinned! :)

[Edit] Now that you have your particles colliding, you can lower the resilience on the geo-connector for that particle shape to lessen the bounce factor if they are too bouncy!

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