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Joint Issue with additional Velocity/Force induced + stiffness

Topics: Developer Forum
Nov 13, 2010 at 6:33 PM

Hey again,

while playing around some more i ran into the following situation where movement is
beeing created without any external influence. To illustrate i made the "ski" a static
body and turned off all mouse->target angle updates.

Any ideas how to prevent that ?


On a second note i am still not finding a way to make constraints more "rigid" and "stiff".
Things tend to stay quite "wobbly" and soft and i'd like to make things a lot more stiff
and less bouncy. Any ideas ? Or would i have to implement some kind of custom constraint
solver like featherstone to do so ? And IF so, would that be possible at all ?


Kind Regards and thanks in advance,


Nov 14, 2010 at 2:17 AM

That looks wierd! What type of joints are you using? 

The only thing I can think of is if the bodies are colliding, or if you have joints going against each other (ie. a revolutejoint with limits or motor and an angle joint)

Id also suggest going through your code again just to make sure you haven't missed something. Make sure the joints are only changed during creation and that no motors enabled.

Nov 14, 2010 at 11:46 AM

Thanks Robert. I think it might be Angle and RevoluteJoints fighting. I guess i need to clamp the target angle to the limits of the RevoluteJoints.

As for the bouncyness i found out that raising the Velocity Iterations helps TONS. Will have to check and see how that affects performance

once there is actually something more happening. I wonder if it would be feasible to have iteration multipliers for joints ? So iterations are raised only when needed

while solving important/unstable joints.