dynamica 101

Physics APIs, Physics file formats, Maya, Max, XSI, Cinema 4D, Lightwave, Blender, thinkingParticles™ and other simulation tools, exporters and importers
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jimberndt
Posts: 3
Joined: Fri Jul 16, 2010 11:08 pm

dynamica 101

Post by jimberndt »

I have run some test using dynamica but there are certain basic things I would like someone to help me grasp. I've looked in the forums and downloaded some test scenes which are primarily cubes or donuts, etc. I am assessing how far I can take the tool for some production we are doing.

I am using the dynamica 2.76 plugin in Maya 2010 64 xp 64.


Here's one question: Why, when I create active bodies (hull or mesh methods) upon collision they self attract?

(See first attachment)

Here's another one: I understand that most solvers that have intersecting geometry start the sim "exploding"... some allow you to control the collision thickness, and some even allow you to start the sim "sitting" on each other... I don't quite get how Dynamica handles this. The second file I am attaching has a cube broken into pieces that touch each other, there's a slight ejection between the pieces ... is .1 the minimum distance I need in order to avoid this ejection? What would it be the procedure if I design say, a building or an object that needs to break from a whole to pieces? Someone seems to be able to do it using Dynamica (see "B breaking" link http://www.youtube.com/watch?v=k4tbOW5b ... re=related), for test file, see attached second file. I would love if someone would post such a file in the forum or explain how to get there.

Another questions is in regards to the bounciness of objects... How do I control that attribute? (See third file).

Any one who could shed some light or point me in the right direction, I'd appreciate it. Some more sample files or tutorials would be great. I am impressed at the speed at which dynamica resolves sims.

Thanks in advance, Jim.
Attachments
RBD_tests.rar
(138.18 KiB) Downloaded 420 times
jimberndt
Posts: 3
Joined: Fri Jul 16, 2010 11:08 pm

Re: dynamica 101

Post by jimberndt »

Hello Jim, this is your alter ego. I want to reply to your recent post with some helpful information.

1. When you create active rigid bodies do not freeze transform them. The reason they "self-attract" is because all of the bodies are trying to go to 0 0 0. The scale of the object needs to be 1 1 1, so feel free to freeze transform those, but do not do it for the actual translation.

2. Collision distance seems to in fact, be .1, in other words, your objects need to be separated by .1. I don't seem to be able to simulate objects that sit on each other so I don't know what to tell you. Maybe someone here can help you. I have no idea how they did the "B" sim that you linked to. Anyone?

3. Bounciness, well, it is critical that you understand the Restitution attribute specially in the passive body which you want to bounce off of. Of course, they all play nice together but think of it this way, the angular and linear damping will just do that, damp energy, put a 1 in angular and your active rigid because a passive for all intend and purposes. Friction is also pretty self explanatory... so that leaves the Restitution attribute. The higher this value the more it will bounce. See the attached examples.

Hope this helps you and every noob out there. Keep the questions coming.

Jim
Attachments
RBD_answers.rar
(16.34 KiB) Downloaded 439 times
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