rotation collision response?

[Isawyou]

Hi all!
when this impulse based equation can equal to zero:
w'=w+(j/I)*r*n;
n normal contact;j impulse;I inertia; from wiki https://en.wikipedia.org/wiki/Collision_response[^]
seems wrong to me;
I'm just talking about center of percussion! what happen to angular velocity?http://labman.phys.utk.edu/phys135/modu ... ge3294.gif it's zero right, not working in impulse based method(and also the sens of angular velocity, I get it always wrong)!
can somebody give a source code about how to calculate angular velocity, or just give me some implementation examples, please I'm lost thanx!

[Dirk Gregorius]

It looks as if a cross product is missing. It should be r x n. Here is a good derivation:
http://www.essentialmath.com/AngularImpulse.pdf

[Isawyou]

well! thanks I figure that out!

[Isawyou]

I have two points manifold, should I apply W to them both?
c for center;p1 and p2 contact point ;

-----------------c-----------------
p2_________________ p1

this bar won't fall!


--------------------------c-----------------------
p2|___________| p1

this bar will fall!

[Dirk Gregorius]

You apply equal and opposite impulses at each contact point. Each off center impulse will indeed affect the angular velocity. I don't want to sound offensive, but you might want to study some basic rigid body mechanics before trying to implement a physics engine.

[Isawyou]

I'm doing my best!

[Dirk Gregorius]

Good luck!

[Isawyou]

Is v=w*r a cross product too? is r a vector or magnitude? how to calculate v=wr?(that's crazy if there is vx and vy in 2d)