Jar of Marbles

[ArgleBargle]

I've lathed a jar that's supposed to hold a bunch of marbles one of my characters later pours into a dish. I figured either the rigid-body thing or the Newton plugin would do the job. I went with Newton.

 

Marbles are clones of the 32-patch sphere and are used as Dynamic Sphereobjects [sic]. The jar is "Static with Action." I put 24 marbles in a semi-random vertical stack over the jar and ran the simulation. The marbles all pooled at the bottom of the jar in a likeable fashion. So far, so good.

 

Later in the chor I lifted the jar and, to my horror, the marbles all simply fell through the bottom of the jar as if it wasn't there. This included the marbles that were sufficiently above the surface of the jar due to resting on other marbles.

 

Experiments with one marble only confused me. The jar would lift and rotate to dump it out and, depending on how fast the jar was rotated, would:

1) roll out of the jar as expected

2) catch for a moment as it passed partway through the inner surface of the jar

3) roll right through the wall as if it wasn't there.

 

So far, the things I've tried that I hoped would cure the problem (but didn't) are:

* Updated from v12 to v13 to get the newest Newton (and everything else, but I'm not really seeing a difference in anything except the new version control stuff)

* putting a sharp edge to the inside edge of the jar

* making it bowl shaped at the bottom

* Increasing patches

* Decreasing them

* Enabling the "Scale world" option [see note below]

 

Since my project is fairly large, I stepped away from it and tried a blank project and new objects. Actually, I copied and pasted the jar splines from my big project to the little one as a test. I couldn't reproduce the problem on a small scale. But "small" also occurred to me. My jar in the small project was roughly 3 times larger than the one I had problems with. That's the reason I resorted to switching to v13 to get the "Scale world" option. According to the docs, the scale option increases things x10 if you're using "small" models. (What qualifies as "small" isn't described).

 

Having said that, I went back to the small project and tried shrinking the jar to the dimensions in my real project and the problem manifested itself. I'll post a followup to this. (I'm writing this from a mac annd the project is on a PC.)

 

So, my question: how can I make this work? As previously mentioned, increasing patches didn't help, nor did "Scale world." I'm at a total loss and can't figure another way to make this work (other than blowing weeks of work by re-scaling everything else in the chor).

 

 

Here are the projects.

The working one: [attachmentid=23101]

The non-working one: [attachmentid=23102]

rollaround.prj

rollaroundbad.prj

[the_black_mage]

did you give the marbles bones? if you did that might be it....

[ArgleBargle]

Nothing other than the basic model bone. You don't get much choice about that one. If you load up the projects, you'll see the problem. Oddly, it's not deterministic. I got the marbles to roll around in the jar in the successful project, but later, I loaded the same project and the marbles fell through. Re-run the sim, some fall through, re-rerun again, it works, fine. Try again and get more random results. Physics isn't supposed to work that way.