Six degrees of freedom (6DoF) explained

Any machine or motion system has differences between the way that it's designed to move and the way that it moves in reality. In many cases, the planned motion is to travel along a perfectly straight line until the exact target distance has been reached.
However, in practice there will always be six different types of error in the linear motion. These are:
• linear
• horizontal straightness
• vertical straightness
• pitch
• yaw
• roll
For systems with more than one linear motion path (e.g. a three axis CNC machine tool) the six types of error in each path will add together to form the overall motion error.