If you are traveling along a space curve, the following three vectors are meaningful in describing your motion.

• T, the unit tangent vector representing your forward direction
• N, the unit normal vector, giving the direction in which your path is turning, and
• B, the unit binormal vector, defined B = T x N

Vector B is related to the tendency of the motion to "twist" out of the plane created by T and N. Together, T, N, and B define a moving right-handed vector frame that plays a significant role in calculating the paths of particles moving through space. The TNB frame is also called the Frenet frame.

This applet was developed for use with Interactive Calculus, published by Pearson.