Differential Geometry/Vector of Darboux

We consider the rotation of the body formed by the three vectors t, p, and b. We define the rotation vector d as follows:

1. d is in the direction of the axis of rotation.
2. d points in the direction such that the rotation is clockwise in that direction.
3. |d| has the value of the angular velocity of the rigid body, or the velocity when at a distance of 1 away from the axis of rotation.