Magnetic-Joint dialog-box

Use the Magnetic-Joint dialog-box to edit the settings of a Magnetic-Joint.


The Magnetic-Joint is an unusual Joint for MechDesigner.

'Standard' : Motion-Dimension FB and motion-values

Usually, motion-values at the input-connector to a Motion-Dimension FB specify the motion of a Motion-Part.

The motion-values at the input to the Motion-Dimension FB are predictable and planned.

'Magnetic' : Motion-Dimension FB and a Magnetic-Joint

A Magnetic-Joint makes a circular profile in a Motion-Part have continuous contact with a irregular* Profile in a different Part.

The motion of the Motion-Part becomes a 'driven-Part'. Its motion becomes a function of the motion and shape of the Part with the irregular* Profile.

The Magnetic-Joint calculates that motion-values [positional, velocity and acceleration] for the Motion-Part

Note: * the shape of the irregular Profile can be derived from a Point-Cloud or a sketch-loop.

Open the Magnetic-Joint dialog box

Note: If you need to add a Magnetic-Joint, see Add Magnetic-Joint.



1.Double-click a Magnetic-Joint FB icon in the graphic-area.

- or -

1.Click the Magnetic-Joint FB in the graphic-area
2.Right-click the Magnetic-Joint FB in the Selection-Window
3.Click 'Edit'

- or -

1.Double-click the Magnetic-Joint FB in the Assembly-Tree

Magnetic-Joint dialog-box


The Magnetic-Joint dialog-box has two separators:

Curve Following Options...

Radius Control

tog_minus        Curve Following Options 


'Enable Magnetic-Joint' check box is active

The circular Profile becomes in continuous contact with the irregular Profile or Point-Cloud.

'Enable Magnetic-Joint' check box is cleared.

The circular Profile is not in continuous contact with the irregular Profile or Point-Cloud.

Magnetic Joint - Outside Following


The refers to the relative position of the circular profile and the irregular Profile.

The image shows the 'Curve Following Profile'1s-red on the outer side of the 'Curve Shape Profile'2s.


Magnetic Joint - Inside Following

Curve Following Side - Inside

The image shows the Curve Following Profile1s-red on the inner side of the 'Curve Shape Profile'2s

tog_minus        Radius Control 



Optionally, modify the effective radius of the Cam-Follower Roller.

'Not Overriding Circle Radius' [default]

The Circular Profile moves along the Irregular Profile.

The 'Radius' parameter is now 0mm and Read-Only

'Modify Circle Radius

Click the check box to be able to overlap of the Circular Profile relative to the 'Irregular' Profile.

Radius parameter box.

When the Radius parameter is '0mm', the Centre of the Circular Profile moves along the Irregular Profile as normal.
When the Radius parameter is '3mm', the Centre of the Circular Profile is 3mm inside the Irregular Profile.

Magnetic Joint - Pich Circle Following

This is useful if you use a CMM machine with a probe diameter that is different to the Cam-Follower Roller, and the CMM software does not have 'Probe Compensation'.

When the CMM data does not compensate for the Probe Diameter, you would set the offset Radius to recreate a Cam-Follower system.

Offset Profile Radius = Radius of Actual Cam-Follower – Radius of CMM Probe

R = Rcf – Rp

Rcf = Cam-Follower Radius; Rp = CMM Probe Radius.

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd