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Chrusion
02-13-2014, 03:07 PM
Why is Bullet barfing so badly on this simple scene and object (attached) consisting of an array of 3,000 slightly squashed cubes in one layer and two identical containers in different layers... one to receive, one to pour out of.

I've set Glue on the Parts object array to 0% in order to have them shift/break apart into a random sorting (self collision due to Collision Margin) during the first dozen frames, BUT then they DO NOT collide with the containers!! 60-70% of them pass right thru the walls. Adding ANY amount of Glue on the Parts object (array), even to the very smallest amount allowed of 0.0001, results in the array NOT breaking apart inside the pouring container (remains a cubical stack even while being poured). With Glue the array DOES collide with the containers.

Why?

I've tried various amounts of Friction and Linear and Angular damping. 100% for all results in gravity NOT working (array doesn't fall and container collision still disrepected).

lertola2
02-13-2014, 07:37 PM
I think you need to increase the dynamics frame rate (on the World tab of the Bullet panel). I have your scene calculating now with a 300 setting. It is a lot better but some cubes are still escaping. Maybe try 600 or even 1000 if you have time to let it calculate. Since your parts are rectangular you might be able to increase calculation speed a bit by setting the shape to box instead of mesh. I have not tested this but it might help to subdivide your cup shapes so there is more geometry for the cubes to collide with.

Chrusion
02-14-2014, 07:48 PM
Thanks for checking. 1000? Wow! That would like take all day to calc.

Anyway, I went with an easier, faster "solution," albeit not physically accurate by a long shot, but the client won't know the difference. I used Hard FX on a cloud of 6,000 single-pt polys. I used a bounce plane at 0% bounce to start the point cloud falling as the plane moved up thru the cloud, a second bounce plane moving upward from the bottom of the cup to get the volume top surface bounce I desired, and a third collision plane parented to the 2nd plane and set to event to stop the points from falling.

lertola2
02-16-2014, 08:29 PM
That sounds like an interesting solution. Any chance you could show what that looked like? I did calculate your original scene at 1000 on my home computer so it ran over night and while I was at work the next day:


http://youtu.be/BLwm5SOUPwE

Chrusion
02-17-2014, 09:28 PM
Looks like you added Glue. What amount? Or did you reduce collision margin to 1mm or less so that the cubes don't partially "explode" into an initial jumbled "mess," which is what I was after, but probably not visually needed since I'm not showing the source of the falling objects?

RE. the Hard FX solution, yeah, I've got it in the queue to render. When done I'll post the clip and the setup scene.

Chrusion
02-18-2014, 11:22 AM
Gonna take too long to get the scene rendered, so I'll just attach the setup/motion baking scene...

lertola2
02-24-2014, 07:28 PM
Looks like you added Glue. What amount? Or did you reduce collision margin to 1mm or less so that the cubes don't partially "explode" into an initial jumbled "mess," which is what I was after, but probably not visually needed since I'm not showing the source of the falling objects?

RE. the Hard FX solution, yeah, I've got it in the queue to render. When done I'll post the clip and the setup scene.

I did change the shape type to box from mesh. I thought that might speed up the calculation.


Gonna take too long to get the scene rendered, so I'll just attach the setup/motion baking scene...

Hmm, nothing is moving the attached scene that I can see. What is supposed to happen? I tried to calculate the FX but nothing is moving.

Chrusion
02-24-2014, 08:28 PM
Strange. All the collision planes are gone! Hmmm... just tried rebuilding and now gravity (no falloff) is "running out of juice" on the falling vertices of the HFX object. Meaning they begin falling at a logarithmic rate, but then come to a stop before entering the collision container. I'll start from scratch tomorrow, refresh the Zip, and post here when done.