Search found 463 matches

by Basroil
Sun Mar 20, 2016 4:06 am
Forum: General Bullet Physics Support and Feedback
Topic: Directional Friction
Replies: 5
Views: 1735

Re: Directional Friction

DannyChapman wrote:What's wrong with the btCollisionObject::setAnisotropicFriction function?!
I completely forgot about that :shock:
by Basroil
Fri Mar 18, 2016 2:19 am
Forum: General Bullet Physics Support and Feedback
Topic: Scan area for intersecting shapes.
Replies: 8
Views: 2534

Re: Scan area for intersecting shapes.

You can always make a ghost shape (same shape you want to test, but doesn't really collide) and see if there's collision. If you don't care too much about exact quality you might even be able to just use broadphase, which will likely be faster
by Basroil
Fri Mar 18, 2016 2:17 am
Forum: General Bullet Physics Support and Feedback
Topic: Directional Friction
Replies: 5
Views: 1735

Re: Directional Friction

You can try implementing anisotropic friction with a custom collision callback. (http://www.bulletphysics.org/mediawiki- ... d_Triggers)

You might be able to get away using mostly default friction code as your base
by Basroil
Wed Mar 16, 2016 6:19 am
Forum: General Bullet Physics Support and Feedback
Topic: Strange behavior due btHingeConstraint
Replies: 1
Views: 991

Re: Strange behavior due btHingeConstraint

Sounds like you're passing in an undefined variable somewhere in your code and the hinge is trying to hit an impossible target.
by Basroil
Fri Mar 11, 2016 8:23 am
Forum: General Bullet Physics Support and Feedback
Topic: equivalent constraint
Replies: 2
Views: 1644

Re: equivalent constraint

Construction wise they should be similar, but their motion is going to be very different in one key situation due to sampling differences. Take for instance a cable vibrating with a certain velocity such that nodes rotate opposite of the adjacent nodes. Now imagine that the frequency and vibration s...
by Basroil
Thu Mar 10, 2016 4:26 am
Forum: General Bullet Physics Support and Feedback
Topic: Help with constraints
Replies: 1
Views: 1519

Re: Help with constraints

The frames are the transformation to the constraint axis in the local coordinates of the bodies involved (frameInA is from A to the axis in terms of A, frameInB is from B to the axis in terms of B)
by Basroil
Mon Mar 07, 2016 1:51 am
Forum: General Bullet Physics Support and Feedback
Topic: Constraint to prevent a motorcycle from falling over
Replies: 1
Views: 1182

Re: Constraint to prevent a motorcycle from falling over

I think you forgot that the world itself can be used. Physics wise though, you're better off just making a controller that shifts a "driver" left and right to balance it like a real bike, since once you put in real graphics now you'll have a physics controlled driver at zero cost (well, some cost in...
by Basroil
Tue Mar 01, 2016 4:36 am
Forum: General Bullet Physics Support and Feedback
Topic: Strange behaviour (sliding without reason)
Replies: 2
Views: 1575

Re: Strange behaviour (sliding without reason)

That just looks like a case of m1v1==m2v2 with near zero friction. Basically, if you put your robot on a air hockey table it would do the same thing. Try increasing the ground and body friction components if they don't match physical results, and if the components are already high consider smaller t...
by Basroil
Tue Mar 01, 2016 3:44 am
Forum: General Bullet Physics Support and Feedback
Topic: Tilting Table - kinematic body force exerted on rotation
Replies: 8
Views: 3646

Re: Tilting Table - kinematic body force exerted on rotation

You should start by reading https://msdn.microsoft.com/en-us/library/windows/apps/mt228373.aspx and checking the source code. You can see how they deal with cameras and physics for exactly what you want to do. After that, go to a library and try to find "Introduction to Robotics: Mechanics and Contr...
by Basroil
Tue Mar 01, 2016 1:50 am
Forum: General Bullet Physics Support and Feedback
Topic: Is rayTest thread safe?
Replies: 9
Views: 3313

Re: Is rayTest thread safe?

svedach wrote:I could not get. I did as it is written at the link above, but when I call rayTest from multiple threads, the heap error occurs. It's a pity.
Are you sure that your threads are off while stepping the world and only polling the system between steps?
by Basroil
Sat Feb 27, 2016 2:18 am
Forum: General Bullet Physics Support and Feedback
Topic: Tilting Table - kinematic body force exerted on rotation
Replies: 8
Views: 3646

Re: Tilting Table - kinematic body force exerted on rotation

That part is all trig actually, it should be as simple as multiplying out the transform from one to the other. Basically you need to find the "contact" area (really just a close approximation should minimize issues) on the box and then extend the rotation from there to the center of gravity. Another...
by Basroil
Fri Feb 26, 2016 12:43 pm
Forum: General Bullet Physics Support and Feedback
Topic: Tilting Table - kinematic body force exerted on rotation
Replies: 8
Views: 3646

Re: Tilting Table - kinematic body force exerted on rotation

The jumping is just physics acting as it should, so what you'll probably need to do is change the "physics". Rather than rotating the box about it's center of gravity, rotate it about the marble's contact point. That should change the angle of the box without changing the position of the box relativ...
by Basroil
Wed Feb 24, 2016 2:15 am
Forum: General Bullet Physics Support and Feedback
Topic: Ray Tracing for LIDAR. How does bullet ray test work.
Replies: 2
Views: 2183

Re: Ray Tracing for LIDAR. How does bullet ray test work.

None of the 2.83 ones are hardware accelerated last I checked, but you should be able to test on multiple threads just fine. Just watch out for possible internal cache errors.
by Basroil
Mon Feb 22, 2016 5:38 am
Forum: General Bullet Physics Support and Feedback
Topic: Bullet on GPU
Replies: 128
Views: 205184

Re: Bullet on GPU

Quick question, if opencl support is so fragile, why don't we use opengl compute? For one, opengl compute support is even more fragile, having only been added in 4.3 and not really designed for this type of application. So far the only real competitor is CUDA, but that of course requires Nvidia har...
by Basroil
Sun Feb 14, 2016 10:59 am
Forum: General Bullet Physics Support and Feedback
Topic: Imitation sensor field of view.
Replies: 3
Views: 2152

Re: Imitation sensor field of view.

Well, thanks for your reply. I understand the principles of operation of the ultrasonic sensor, I have made a model based on rayTest, but I was not satisfied with the performance. I do not want to use the cone. It does not correctly represent the field of view of the sensor. I use the trapeze. Can ...