﻿ MotionDesigner Reference & User Interface > Motion Laws > Flexible-Polynomial Motion-Law > Throw - Quick-Return: 1: Finite Jerk @ Start/End Motion-Law

# Throw - Quick-Return: 1: Finite Jerk @ Start/End Motion-Law

### Throw: Quick-Return 1: Finite Jerk

Quick-Return=1

is not in the Motion-Law Selector.0

Quick-Return-1 motion-law is a Rise & Return motion-law.

It is continuous in Position, Velocity and Acceleration.

Construct the 'Quick-Return 1' motion with two Flexible Polynomial Segments.

The first segment is the Rise, and the second segment is the Return. Each segment is a 'mirror' of each other.

Usually, the segments have an equal duration, but this is not necessary.

Continuity at the Mid-Point Blend-Point

At the mid-point, the Position is at a maximum value [in the image, max P=1], and the Velocity is zero.

At the mid-point the segments both have a finite, negative acceleration.

The acceleration is continuous. The Jerk is also continuous and zero at the mid-point.

We can call this a Quick-Return Motion because at the point where the Rise becomes the Return, there is a negative, but continuous acceleration.