Jump to content

  • Log In with Google      Sign In   
  • Create Account


(Impulse) Change in Angular Velocity or Angular Momentum?


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
1 reply to this topic

#1 Irlan R.   Members   -  Reputation: 1273

Like
0Likes
Like

Posted 13 March 2013 - 09:11 AM

I'm implementing a physics simulation for my final course project and updating the rigid bodies like this:
 
calc_forces(); //calc constant forces and torques
 
velocity += (force / mass) * dt;
position += velocity * dt;
 
ang_momentum += torque * dt;
orientation += ( (ang_vel * orientation) * 0.5f ) * dt;
 
orientation.normalize();
 
ang_vel = inverseInertia * ang_momentum;
 
 
//IF COLLIDE WITH OTHER
 
velocity += ( (j * collision.cn) + (u * j) * collision.ct ) / mass;
ang_vel += pt1.cross( (j * collision.cn) + (u * j) * collision.ct ) * inverseInertia;
 
other.velocity += ( (-j * collision.cn) + (u * j) * collision.ct ) / other.mass;
other.ang_vel += pt2.cross( (-j * collision.cn) + (u * j) * collision.ct ) * other.inverseInertia;
 
I've read the Baraff's papers but i think that what i'm doing is "no change in angular momentum" and in this moment I don't have any idea how to calculate.
Obs: when i change ang_vel to ang_momentum, the results are better but i want correctly results. 


Sponsor:

#2 EWClay   Members   -  Reputation: 655

Like
0Likes
Like

Posted 13 March 2013 - 03:22 PM

The only obvious problem is that you are changing angular velocity in the collisions and overwriting it in the update, so the change would have no effect. As you seem to realise, changing angular momentum is better.

If it still looks wrong, there could be plenty of reasons that are unconnected to the code above.




Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS