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# Dialog: Ball-Joint

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# Dialog: Ball-Joint

## Ball-Joint

See: Add Ball-Joint. Tutorial 12: Design a Spatial Mechanism

Use the Ball-Joint for spatial mechanisms.

You must add a Ball-Joint to each end of one Part.

Connecting-Part : the derived name of a Part that has a Ball-Joint at each end.

One of the two Ball-Joint joins the Connecting-Part to a Part in a different Mechanism-Editor.

The other Ball-Joint, at the other end of the Connecting-Part, joins it to a Part in the active Mechanism-Editor.

#### How to open the Ball-Joint dialog-box

There are two Ball-Joints, with one at each end of a Connecting-Part.

The Ball-Joint element may be inside the symbol of the Connecting-Part.

 1.Move your mouse-pointer above the end of the Connecting-Part until the Ball-Joint is red - see image. 2.Click the symbol for the Ball-Joint. The Ball-Joint element should be in the Selection-Window 3.Right-click the Ball-Joint in the Selection-Window 4.Click Edit Element in the contextual-menu.

Ball-Joint in the Selection-Window

The Ball-Joint dialog-box is now open.

### Ball-Joint dialog-box

Ball Diameter

 Diameter of the Ball symbol in graphic-area. Ball-Diameter does NOT effect the Kinematic-Analysis.

Ball Offset (±)

 Perpendicular distance (±) from the Mechanism Plane to the center of the Ball-Joint. Ball-Offset does effect the Kinematic-Analysis.

Ball Mass

 Mass of the Ball-Joint. Its center-of-mass is coplanar with the Mechanism-Plane. even if the Ball-Offset ≠ 0.

Example of Ball-Offset : Z = 10mm

<<< the image shows the model from the left view - View toolbar > View Left (Shortcut : F7).

Ball-Joint : on the Mechanism-Plane when Ball-Offset = 0mm.

In the image the Ball-Offset = +10mm in the +Z-axis direction.

When to use the Ball-Offset parameter?

The symbols of all other kinematic-elements are on the Mechanism-Plane. However, the center of a Ball-Joint is frequently not on the Mechanism-Plane.

The kinematic-analysis is correct only when the distance from the Mechanism-Plane to the center of the Ball-Joint is correct.