# 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:

**d**is in the direction of the axis of rotation.**d**points in the direction such that the rotation is clockwise in that direction.- |
**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.