﻿ MechDesigner Reference & User Interface > 2.2 Mechanism-Editor: > Kinematic elements > Mechanism | Add Slide-Joint

#### Terminology

 Technical Definition: Prismatic Joint : A joint that only allows relative rectilinear translationmotion between two Parts (rigid bodies). MechDesigner definition : Slide-Joint : A joint, between two Parts, that forces a Line in one Part to be collinear with a Line in the other Part. Line : A Line specifies an axis on a Part. The position of the axis is specified by two Points that are on the Mechanism-Plane. Points : The Points at each end of a Line are termed the start-Point and end-Point. The XY-Plane of all Parts (and the Base-Part) in a Mechanism-Editor are coplanar with the Mechanism-Plane.

### A Slide-Joint in the Graphic-Area

Slide-Joint

A Slide-Joint is defined by a Line that you select in two different Parts.

The symbol for the Slide-Joint is:

 A Narrow Rectangle that is equal to the length of the Line in one of the Parts. A Wide Rectangle that is equal to the length of the Line in the other Part. Arrowhead - the Positive-Direction* of the Slide-Joint.

* Positive-direction is important if you want to add a motion to the Slide-Joint.

IMPORTANT: To calculate reaction forces for a Slide-Joint:

The length and position of the Lines that define the Slide-Joint must be equivalent to actual design.

Select two Lines

A New Slide-Joint

STEP 2: Click the two(2) Lines

 1.Mechanism-Editor: Click a Line in a Free-Part 2.Mechanism-Editor: Click a Line in a different Part

The two(2) Lines become collinear to add the Slide-Joint.

The Positive Direction of the Slide-Joint is identified by the small arrowhead.

If the Select-Elements dialog-box opens, see Slide-Joint Special Case