Rigidbodys velocity

Hi!
I have a problem measuring a rigidbodys velocity, what is the best way to do that, without having the angular velocity into account. thankful for any answers.

overall velocity? I would use rigidbody.velocity.magnitude.

Relative velocity can be measured by:

relativeVelocity = transform.InverseTransformDirection(rigidbody.velocity);

Z would be forward, Y, up and X left and right.

thank you that was just what i was looking for.