Conservation?
Posted: Wed Nov 30, 2016 10:02 pm
Hi everybody.
I have a question about conservation in BulletPhysics.
In the world of Newtonian mechanics (classical physics), there are 7 conserved quantities: energy, 3 components of angular momentum and 3 components of momentum.
In the world of BulletPhysics, a very simple test indicates that the 3 components of momentum are conserved, but the 3 components of angular momentum are not conserved and therefore energy is not conserved.
My simple test involves firing two spheres at each other on trajectories that are parallel but not co-linear. Therefore, the spheres collide in a glancing blow. Here are the results...
Scenario 1: When There Is No Friction, It Works
When the spheres have zero friction, then the glancing blow does not cause the spheres to rotate during or after the collision. The 3 components of momentum are conserved and there is no rotation (no angular momentum) and the total energy of the system is conserved.
Scenario 2: When There Is Friction, It Doesn't Work
When the spheres have friction, then the glancing blow causes both spheres to rotate during and after the collision. The 3 components of momentum are conserved, but the angular momentum is not conserved and therefore the total energy of the system is not conserved.
Does BulletPhysics provide a solver and/or any params that would allow this experiment to work in Scenario 2 above?
Thanks!
I have a question about conservation in BulletPhysics.
In the world of Newtonian mechanics (classical physics), there are 7 conserved quantities: energy, 3 components of angular momentum and 3 components of momentum.
In the world of BulletPhysics, a very simple test indicates that the 3 components of momentum are conserved, but the 3 components of angular momentum are not conserved and therefore energy is not conserved.
My simple test involves firing two spheres at each other on trajectories that are parallel but not co-linear. Therefore, the spheres collide in a glancing blow. Here are the results...
Scenario 1: When There Is No Friction, It Works
When the spheres have zero friction, then the glancing blow does not cause the spheres to rotate during or after the collision. The 3 components of momentum are conserved and there is no rotation (no angular momentum) and the total energy of the system is conserved.
Scenario 2: When There Is Friction, It Doesn't Work
When the spheres have friction, then the glancing blow causes both spheres to rotate during and after the collision. The 3 components of momentum are conserved, but the angular momentum is not conserved and therefore the total energy of the system is not conserved.
Does BulletPhysics provide a solver and/or any params that would allow this experiment to work in Scenario 2 above?
Thanks!