Real-Time Physics Simulation Forum

Re: Bullet 2.83 released on github

2017-02-23T10:18:27+00:00

The feature to include the gyro terms in the solver is excellent - it turns out to be really important for correct simulation of aircraft spins and snap rolls etc, so much appreciated. I'll post a video of it in my R/C flight sim shortly.

Thanks - Danny
Have you posted your video already? If yes, where can I view it?
Ooops I forgot! https://youtu.be/LwjFUzsymjE

The manoeuvres most affected are the flat spin right at the end of the video, and also the "flips", for example around 2:25 - if they don't start perfectly aligned with the wing span then the glider "wobbles" out after a few rotations (not shown here). Before I included the gyro term it would happily continue to rotate around a slightly "off" axis, which is wrong.

Here's the designer of the plane flying the real thing (including the gyro terms!): https://youtu.be/6VZ0tRrXnKA

Watched both the videos. All I can say is "Brilliant"!

Statistics: Posted by kownwong — Thu Feb 23, 2017 8:08 am

Re: Bullet 2.83 released on github

2017-02-21T23:06:33+00:00

The feature to include the gyro terms in the solver is excellent - it turns out to be really important for correct simulation of aircraft spins and snap rolls etc, so much appreciated. I'll post a video of it in my R/C flight sim shortly.

Thanks - Danny
Have you posted your video already? If yes, where can I view it?

Ooops I forgot! https://youtu.be/LwjFUzsymjE

The manoeuvres most affected are the flat spin right at the end of the video, and also the "flips", for example around 2:25 - if they don't start perfectly aligned with the wing span then the glider "wobbles" out after a few rotations (not shown here). Before I included the gyro term it would happily continue to rotate around a slightly "off" axis, which is wrong.

Here's the designer of the plane flying the real thing (including the gyro terms!): https://youtu.be/6VZ0tRrXnKA

Statistics: Posted by DannyChapman — Tue Feb 21, 2017 11:06 pm

Re: Bullet 2.83 released on github

2017-02-18T14:58:19+00:00

The feature to include the gyro terms in the solver is excellent - it turns out to be really important for correct simulation of aircraft spins and snap rolls etc, so much appreciated. I'll post a video of it in my R/C flight sim shortly.

Thanks - Danny

Have you posted your video already? If yes, where can I view it?

Statistics: Posted by kownwong — Sat Feb 18, 2017 2:58 pm

Re: Bullet 2.83 released on github

2016-12-28T17:05:28+00:00

So what's on the plate for the future? I see some work in featherstone btMultiBody stuff...

I also see some logic for tracking 'islands'.. which I guess are groups of related things that might collide.
I would think that as an extension my crazybulk review by thisfitlifestyle to that one might order collisions based on their collision with static bodies; such that if a body collides with a static body it gets an additional flag set in it that indicate it's a static collidable; would think that would solve issues stacking heavy things on light things. (been doing a lot of reading and now see where that artifacting comes from). Then the 'roots' of islands would process first and then tree out from there... but maybe then 2 bodies on a static ground next to each other would still have issues.

Also digging through collision dispatch and DISPATCH_CONTINUOUS is never actually used? Isn't that kinda what discretedynamicsworld/CCD would need? to precalculate the penetration depth to determine a more appropriate time step before doing the discrete resolutions?

I wish there was more info out there on this, don't take me wrong github has the read me file but i am lookig for a video tutorial

Statistics: Posted by Riley — Wed Dec 28, 2016 5:05 pm

Re: Bullet 2.83 released on github

2016-03-16T15:28:00+00:00

Any news on this?

Statistics: Posted by aaronhansome — Wed Mar 16, 2016 3:28 pm

Re: Bullet 2.83 released on github

2015-11-14T04:54:45+00:00

So what's on the plate for the future? I see some work in featherstone btMultiBody stuff...

I also see some logic for tracking 'islands'.. which I guess are groups of related things that might collide.
I would think that as an extension to that one might order collisions based on their collision with static bodies; such that if a body collides with a static body it gets an additional flag set in it that indicate it's a static collidable; would think that would solve issues stacking heavy things on light things. (been doing a lot of reading and now see where that artifacting comes from). Then the 'roots' of islands would process first and then tree out from there... but maybe then 2 bodies on a static ground next to each other would still have issues.

Also digging through collision dispatch and DISPATCH_CONTINUOUS is never actually used? Isn't that kinda what discretedynamicsworld/CCD would need? to precalculate the penetration depth to determine a more appropriate time step before doing the discrete resolutions?

Statistics: Posted by d3x0r — Sat Nov 14, 2015 4:54 am

Re: Bullet 2.83 released on github

2015-05-13T23:32:11+00:00

Nice!

I wish the Devs @ blender would get this into the game engine.

Statistics: Posted by BluePrintRandom — Wed May 13, 2015 11:32 pm

Re: Bullet 2.83 released on github

2015-05-05T13:44:22+00:00

The feature to include the gyro terms in the solver is excellent - it turns out to be really important for correct simulation of aircraft spins and snap rolls etc, so much appreciated. I'll post a video of it in my R/C flight sim shortly.

Thanks - Danny

Statistics: Posted by DannyChapman — Tue May 05, 2015 1:44 pm

Bullet 2.83 released on github: Example Browser, URDF

2016-10-10T02:21:22+00:00

You can download the Bullet 2.83 release from github here:
https://github.com/bulletphysics/bullet3/releases

See the docs/BulletQuickstart.pdf guide as part of the SDK download.

Some of the features include:

A new example browser, based on OpenGL 3+. It is still work-in-progress and not all demos have been ported over yet. Still, it is a better way to explore the Bullet SDK.
Import of URDF files, universal robot description files. A URDF file can be imported as rigid bodies (btRigidBody) or as multi body (btMultiBody). See the example browser under importers.
Improved support for btMultiBody with multi-degree of freedom mobilizers, thanks to Jakub Stepien. See examples/MultiBody/MultiDofDemo.
New btGeneric6DofSpring2Constraint, replacing the old one. Thanks to Gabor PUHR and Tamas Umenhoffer. See the example browser under API or examples/Dof6Spring2Setup.
OpenCL demo integrated in the ExampleBrowser. The demo is disabled by default. See docs/BulletQuickstart.pdf how to enable it.
Implicit integration of gyroscopic forces. See example browser under API/Gyroscopic for the Dzhanibekov effect.

Please enjoy, and expect improvements in future releases.
Erwin

Statistics: Posted by bullet_team — Mon May 04, 2015 6:38 am