﻿ MotionDesigner Reference & User Interface > Motion Design Considerations > Refresher: Blend-Point and Segments

# Refresher: Blend-Point and Segments

### A Refresher on Segments and Blend-Points in MotionDesigner

 Motion is: 1.A motion evaluates the displacement of a machine element at each instant of a machine-cycle. 2.In addition to the Position, the important motion-derivatives are also evaluated exactly at all machine angles. The process of motion-design specifies at particular instances of the machine cycle the exact values for position, velocity, acceleration, and/or jerk. Mathematical-functions evaluate the motion-values at all instances of the machine cycle. When the motion requirements becomes complex, it is difficult to find a single mathematical-function that satisfies all of the motion's requirements for a complete machine cycle. Therefore, you will usually split, or divide, the machine-cycle into two or more motion-periods that we join end-to-end to give a complete machine cycle. We can then use a different mathematical-function for each motion-period. We use the term Segment for each motion-period. We use the term Blend-Point for each instance in the machine-cycle that we split the motion. Each Segment has a Blend-Point at its start and at its end. Not only do motion-designers need to specify when and where to split the motion into different Segments, they must also select the mathematical function that can best satisfy the motion requirements at all  points in the Segment. The mathematical-functions, from which the user can select, have been chosen by PSMotion to meet the different requirements of most machine designs, each with different applications or advantages. Each mathematical-function is called a Motion-Law or Cam-Law.