Baumgarte 'Jet Propulsion'
Posted: Thu May 29, 2008 6:19 pm
Hello,
After a while trying to figure out the ins and outs of Erin's Box2D method, I finally started implementing it myself.
I implemented an SAT algorithm which clips edges and generates a contact manifold equivalent to box2D's (as far as i know at least, it seems to generate the same points for tested situations).
So I have everything running except for warm starting, but the main problem with my simulation is that (only sometimes) boxes seem to shoot up in the air like popcorn, or even disappear (tunneling through the walls and escaping). I noticed Erin mentioned 'Jet Propulsion' in his slide about Baumgarte.. Is this what you meant?
I'm wondering if anyone here has experienced this violent change is velocities too? I know these problems don't happen with Box2D light (which I'm working off of) so if you've had similar problems please let me know.
Here are the observations I made about this 'bug':
- It happens with and without split impulses, but more often with them
- It becomes worse as the amount of iterations go up
- It also becomes worse with higher bias factors (0.6+)
- It seems to happen when boxes come in contact with two or more other boxes
Any suggestions would be greatly appreciated.
Thanks!
Oz
After a while trying to figure out the ins and outs of Erin's Box2D method, I finally started implementing it myself.
I implemented an SAT algorithm which clips edges and generates a contact manifold equivalent to box2D's (as far as i know at least, it seems to generate the same points for tested situations).
So I have everything running except for warm starting, but the main problem with my simulation is that (only sometimes) boxes seem to shoot up in the air like popcorn, or even disappear (tunneling through the walls and escaping). I noticed Erin mentioned 'Jet Propulsion' in his slide about Baumgarte.. Is this what you meant?
I'm wondering if anyone here has experienced this violent change is velocities too? I know these problems don't happen with Box2D light (which I'm working off of) so if you've had similar problems please let me know.
Here are the observations I made about this 'bug':
- It happens with and without split impulses, but more often with them
- It becomes worse as the amount of iterations go up
- It also becomes worse with higher bias factors (0.6+)
- It seems to happen when boxes come in contact with two or more other boxes
Any suggestions would be greatly appreciated.
Thanks!
Oz