If you do not change direction,you may end up where you are heading.
— Lao Tzu (600–531 BCE)
This chapter tackles the difficult problem of describing the orientation of an object in 3D. It also discusses the closely related concepts of rotation and angular displacement. There are several different ways we can express orientation and angular displacement in 3D. Here we discuss the three most important methods—matrices, Euler angles, and quaternions—as well as two lesser known forms—axis-angle and exponential map. For each method, we define precisely how the representation method works, and discuss the peculiarities, advantages, and disadvantages of the method.
Different techniques are needed in different circumstances, ...