What I have done the last days:
– contact point calculations
– two collision response models (simple & fast + physical accurate)
– different integrators (Euler, Verlet, Mid-Point, RK4)
– basic forces (gravity, spring, attractor, repulsor..)
– dynamic and static friction
So basically the engine is working now. There are some small bugs when handling multiple simultaneous contacts which I’ll solve later. Now it’s time to build a framework, optimize and clean-up the code and convert it to AS3.