I''m trying to implement a 3D physics engine. If someone knows some cool links to learn from... The problem is that I implemented a simple Euler integrator to calculate the new position from the old one and the acceleration but objects movements are jerky...

What kind of forces are you applying to the objects? Euler integrator can work okay when all you have is gravity, but it is a poor, even *evil*, choice when you have other types of forces, especially springs.

Try Chris Hecker''s articles from game developer magazine,

http://www.d6.com/users/checker/index.htm

Or several articles from the GD mag archives (e.g., Jeff Lander''s articles):

http://www.gdmag.com/code.htm

Those are good starting points.

Graham Rhodes
Senior Scientist
Applied Research Associates, Inc.