Search found 463 matches

by Basroil
Thu Nov 30, 2017 4:43 am
Forum: General Bullet Physics Support and Feedback
Topic: Multiple, concurrent simulations
Replies: 4
Views: 1587

Re: Multiple, concurrent simulations

Hey, This is fantastic news! It sounds like you're doing something very similar to what I desire to do. Would you be able to share an example of a previous project? Or of the basic code to achieve these kind of concurrent graphic-less simulations? I have begun implementing parallelisation of simula...
by Basroil
Mon Nov 20, 2017 12:41 am
Forum: General Bullet Physics Support and Feedback
Topic: Multiple, concurrent simulations
Replies: 4
Views: 1587

Re: Multiple, concurrent simulations

I had plenty of success doing just that for some research projects I had. Now that Bullet is more multithread compatible (btDantzig had a memory share bug a while ago that I used to have to manually patch all the time until about 2.82/2.83), it's a piece of cake. Don't bother using the GUI setups an...
by Basroil
Sun May 29, 2016 4:31 pm
Forum: General Bullet Physics Support and Feedback
Topic: [SOLVED] Newton's cradle not transforming force properly
Replies: 2
Views: 1843

Re: Newtonian pendulum not transforming force properly

Took a look at the code and video but haven't added it to my project yet so can't say the following is 100% accurate/going to fix it, but: -Video looks like it's doing what it's supposed to, at least from a theoretical perspective. In one step there's zero motion so zero propagation. Even in real-wo...
by Basroil
Sun May 29, 2016 5:55 am
Forum: General Bullet Physics Support and Feedback
Topic: Discussion of future Bullet Example contributions (Join us!)
Replies: 44
Views: 25055

Re: Discussion of future contributions and roadmap

I was not very up to writing tutorials today, so I created another interesting example showing how to speed up and slow down your simulation. I also include changing the time step size of the simulation and additionally it changes the CFM and ERP according to the descriptions in the ODE wiki. I wil...
by Basroil
Thu May 26, 2016 3:40 pm
Forum: General Bullet Physics Support and Feedback
Topic: Reduce time simulation
Replies: 3
Views: 1437

Re: Reduce time simulation

That code simply means that you want to take a 1 second step using the default parameters (1/60s substep, etc), which doesn't sound like what you want to do. If you aren't using GUI, the method is very easy, just loop the world step command with the substep size as fast as you can, something like: w...
by Basroil
Tue May 10, 2016 1:04 pm
Forum: General Bullet Physics Support and Feedback
Topic: Need help applying euler angles to btTransform[SOLVED]
Replies: 5
Views: 2264

Re: Need help applying euler angles to btTransform

That is not what I need. What I need is to apply correctly angles on a rigid body. First thing should be to find out what your axis definitions are. You have quat.setEulerZYX(rotation.Y, rotation.X, rotation.Z); , where y is yaw, x is pitch, z is roll, but then you have btTransform(quat, btVector3(...
by Basroil
Tue May 10, 2016 4:42 am
Forum: General Bullet Physics Support and Feedback
Topic: Discussion of future Bullet Example contributions (Join us!)
Replies: 44
Views: 25055

Re: Discussion of future contributions and roadmap

You could consider using the Example Browser framework instead of writing yet another framework ;-) ? I plan to add parameter estimation as well, matching parameters a simulated robot with a real robot. Then you get a new URDF file (or SDF file etc) that makes it easier to transfer results from rea...
by Basroil
Mon May 09, 2016 4:16 pm
Forum: General Bullet Physics Support and Feedback
Topic: Discussion of future Bullet Example contributions (Join us!)
Replies: 44
Views: 25055

Re: Discussion of future contributions and roadmap

That is a pity to hear. I would expect the URDF loader to be easy to use to create a btMultiBody. Can't student just use the URDF importer as-is? Why do students need to know how the URDF loader internals are working? Furthermore, you don't need to use inverse dynamics computed torque control, the ...
by Basroil
Mon May 09, 2016 12:57 pm
Forum: General Bullet Physics Support and Feedback
Topic: Discussion of future Bullet Example contributions (Join us!)
Replies: 44
Views: 25055

Re: Discussion of future contributions and roadmap

Basroil, we could also port the old motor control demo and some other old demos and improve them. As soon as I have Erwin's spreadsheet, I can start doing that as well. I had some problems understanding the older demo's setups, but I will get there in time. When I run the URDF demos, I always get b...
by Basroil
Mon May 09, 2016 5:06 am
Forum: General Bullet Physics Support and Feedback
Topic: Discussion of future Bullet Example contributions (Join us!)
Replies: 44
Views: 25055

Re: Discussion of future contributions and roadmap

There are various examples in the Example Browser that allow motorized robots, loading the robot from a .urdf file, using btMultiBody (or btRigidBody+btTypedConstraint, but those joints would be less rigid with the default PGS LCP constraint solver at 10 iterations, hence most prefer Featherstone b...
by Basroil
Sun May 08, 2016 5:01 am
Forum: General Bullet Physics Support and Feedback
Topic: Discussion of future Bullet Example contributions (Join us!)
Replies: 44
Views: 25055

Re: [SOLVED] Discussion of future contributions and roadmap

If they can be run as a standalone application, how do you run them as standalone without a main function, or without the integration of the example browser? I think it would be more beneficial not to use the example browser in future examples. The examples themselves are independent of the applica...
by Basroil
Sun May 08, 2016 3:42 am
Forum: General Bullet Physics Support and Feedback
Topic: Discussion of future Bullet Example contributions (Join us!)
Replies: 44
Views: 25055

Re: [SOLVED] Discussion of future contributions and roadmap

bkeys totally messed up the discussion about improving the Bullet examples etc, so I decided to stop this non-constructive feedback and removed the topic. Documentation in the wiki is welcome, and it would be good to review it and copy parts in the Bullet_User_Manual.pdf. How would you propose we m...
by Basroil
Sat May 07, 2016 4:15 pm
Forum: General Bullet Physics Support and Feedback
Topic: How to keep object stay straight vertically (Roly-poly toy)?
Replies: 2
Views: 3326

Re: How to keep object stay straight vertically (Roly-poly t

Basically your issue here is an inverted pendulum , where your body is the pendulum. Pretty easy in theory, but when you try to add compensation for rotational effects, collisions, etc, it can be more of an art in tuning. Throw in a bit of angular damping and it shouldn't be too difficult to get dow...
by Basroil
Fri May 06, 2016 5:30 am
Forum: General Bullet Physics Support and Feedback
Topic: Forum moderators/custodians/janitors?
Replies: 6
Views: 2768

Re: Forum moderators?

I think the community is small and well mannered enough that a "moderator" isn't necessary, but I do think a "custodian" role might be needed. As you've mentioned, there's often spam and long dead threads around, and it's a bit much to ask Erwin to take care of all of it by himself. Whether that "cu...
by Basroil
Mon May 02, 2016 12:03 pm
Forum: General Bullet Physics Support and Feedback
Topic: Custumizing physics ?
Replies: 2
Views: 1357

Re: Custumizing physics ?

You can theoretically make your own custom solver, but that's a PhD topic's worth of work :wink: For your particular needs, it sounds like you would be better off using smaller time steps with bullet, or moving to a more traditional astronomical multibody method. After all, it seems like most of you...