Search found 54 matches

by steven
Wed May 29, 2019 11:51 am
Forum: General Bullet Physics Support and Feedback
Topic: Incorrect results when simulating multiple bodies
Replies: 8
Views: 345

Re: Incorrect results when simulating multiple bodies

hi tgreif,
sorry, it is hard for me to reproduce your issue. hope next time i can help you. good luck!
by steven
Mon May 27, 2019 12:21 pm
Forum: General Bullet Physics Support and Feedback
Topic: Incorrect results when simulating multiple bodies
Replies: 8
Views: 345

Re: Incorrect results when simulating multiple bodies

Could you tell me the initial postion of these two meshes, as well as some parameters, such as the initial velocity, friction, mass or other values? thanks.
by steven
Mon May 27, 2019 11:19 am
Forum: General Bullet Physics Support and Feedback
Topic: Incorrect results when simulating multiple bodies
Replies: 8
Views: 345

Re: Incorrect results when simulating multiple bodies

Could you attach your stl files and code snippet of how did you create your world? i want to reproduce it and then debug it to find the root cause.
thanks!
by steven
Sun May 26, 2019 2:12 pm
Forum: PyBullet Support and Feedback
Topic: Issues with velocity control
Replies: 5
Views: 432

Re: Issues with velocity control

update the procedure of this case. 1. apply the gravity to the multibody then will change the velocity, 2. apply the constraints, including 1> jointMotor constraint that will try to change the velocity back to the targetVelocity, 0 for your case; 2> Fixed constraint 3> contact constraint and frictio...
by steven
Thu May 23, 2019 6:36 pm
Forum: PyBullet Support and Feedback
Topic: Issues with velocity control
Replies: 5
Views: 432

Re: Issues with velocity control

Could you also attach all the mesh files? thanks.

Code: Select all

b3Printf: ur5_free_base.urdf:24: cannot find 'meshes/ur5/visual/base.dae' in any directory in urdf path
by steven
Thu May 23, 2019 7:21 am
Forum: PyBullet Support and Feedback
Topic: Issues with velocity control
Replies: 5
Views: 432

Re: Issues with velocity control

Could you attach a complete simple test? i can debug it with you to find what happened there. so far my understanding about the procedure: 1. apply the gravity to the multibody then will change the velocity, 2. apply the jointMotor constraint that will change the velocity back to the targetVelocity,...
by steven
Tue May 21, 2019 11:27 am
Forum: General Bullet Physics Support and Feedback
Topic: SoftBody: modeling a rope from trimesh
Replies: 6
Views: 465

Re: SoftBody: modeling a rope from trimesh

i find that there are duplicated vertex in the array of gVerticesRope, the engine will create a node for each vertex when this array is passed to the btSoftBody(), so there will be more than one node for a same point that is not what we expect. i think you need to re-design your gVerticesRope/gIndic...
by steven
Mon May 20, 2019 1:53 am
Forum: General Bullet Physics Support and Feedback
Topic: SoftBody: modeling a rope from trimesh
Replies: 6
Views: 465

Re: SoftBody: modeling a rope from trimesh

Could you first change your mesh? i would like to work with you to find the root cause.
i also noted that the first and last note are not located at the end of this rope.
by steven
Sun May 19, 2019 10:42 am
Forum: PyBullet Support and Feedback
Topic: Joint friction
Replies: 5
Views: 308

Re: Joint friction

you can google the damping then you can know what the damping is used for. the damping force is a resistence that proportional to the velocity but in the opposite direction. as for the implementation in this engine, honestly so far i still don't understand what that equation below comes from. for mo...
by steven
Fri May 17, 2019 9:12 am
Forum: PyBullet Support and Feedback
Topic: Joint friction
Replies: 5
Views: 308

Re: Joint friction

1. p.setJointMotorControl2(obj,1,p.VELOCITY_CONTROL,targetVelocity=0,force=frictionForce)
2. p.changeDynamics(obj,j,linearDamping=value1, angularDamping=value2)

for my understanding, these two get the similar result with different methods. you can try it and see if get what you want.
by steven
Fri May 17, 2019 1:45 am
Forum: PyBullet Support and Feedback
Topic: Joint friction
Replies: 5
Views: 308

Re: Joint friction

self._p.setJointMotorControlArray(self.kuka_uid, self._motor_indices, self._p.VELOCITY_CONTROL, forces=np.zeros(len(self._motor_indices))) i think this is a method to simulate the joint friction, like the angularDamping. self._p.changeDynamics(self.kuka_uid, self._motor_indices, lateralFriction=fri...
by steven
Thu May 16, 2019 12:20 pm
Forum: General Bullet Physics Support and Feedback
Topic: SoftBody: modeling a rope from trimesh
Replies: 6
Views: 465

Re: SoftBody: modeling a rope from trimesh

after removing the "psb->m_cfg.kMT = 0.5;" it will become the one like below which seems that your mesh is constructed of some separate parts.
Collide1.png
Collide1.png (60.61 KiB) Viewed 449 times
by steven
Thu May 16, 2019 8:24 am
Forum: General Bullet Physics Support and Feedback
Topic: RayTest randomly failing
Replies: 5
Views: 271

Re: RayTest randomly failing

i also run it with very high fps with different parameters, but my hit point always is (-5.046927:1.000000:39.472855).

Code: Select all

while(1)
        castRays();
i compile it with double precision enabled, maybe this is the main difference between us.

good luck!
by steven
Thu May 16, 2019 7:37 am
Forum: General Bullet Physics Support and Feedback
Topic: RayTest randomly failing
Replies: 5
Views: 271

Re: RayTest randomly failing

i just do a test with your data, all the result is as expected. from(-5.087273,0.000000,39.472855) to(-5.025157,0.000000,39.472855) hasHit ..........-5.046927:1.000000:39.472855 from(-5.099017,0.000000,39.472855) to(-5.037612,0.000000,39.472855) hasHit ..........-5.046927:1.000000:39.472855 from(-5....