Motion-Path FB

see Add Motion-Path FB

Motion-Path FB

A Motion-Path FB  adds a Motion-Point to a sketch-path.

The Motion-Point is a kinematic-element, to which we can join a Part with a Pin-Joint.

The motion-values at the input-connector to the Motion-Path FB represent the distance of the Motion-Point along the sketch-path.

When the motion-values at the input to the Motion-Path FB are:

Linear Units [mm] at the input:

Distance the Motion-Point moves along the sketch-path = Input Motion-Value mm

Angular Units [degrees] at the input:

Distance the Motion-Point moves along the Motion-Path = Input Motion-Value [degrees] /360


A Sketch-Path is one to many sketch-elements joined end-to-end with Merged-Points

Open[Γ], or
Closed[Δ], or
Crossed[α], or
Not crossed[ε].

Edit the Motion-Path FB


Edit the Motion-Path FB:

1.Double-click the Motion-Path FB in the graphic-area

- or -

Motion-Path FB dialog-box

Motion-Path FB dialog-box

Motion-Path FB dialog-box

tog_minusPoint-Parameters tab


Point Parameters 

Number of Motion-Points:

When Motion-Points > 1 the Motion-Points are distributed equally distributed along the sketch-path.

See also: Regenerate Motion-Points button

Angular Range [deg] [Default 360 : a complete path]

Linear Range [mm]. Default Linear Distance = Length of sketch-path*.


A Path Length is 127.123mm long.

Point Count is 3.

A Range of 360 [default], makes the 3 Points equally spaces with a distance between each Motion-Point = 127.123/3 mm

A Range of 66[deg], makes the 3 Points equally spaced over a total distance of [127.123 * 66 ∕ 360] mm, and the distance between each Motion-Point is [127.123/3 * 66/360].

Phase Offset / Linear Offset: [deg] or [mm]

The position of the 'first' Motion-Point when a wire is not connected to the input-connector of the Motion-Path FB.

When the Offset = 360[degs] or 0[mm], the 'first' Motion-Point is at the start-Point of the sketch-path.

If you generate more than one Motion-Point, the Motion-Points are offset along the sketch-path together.


A Path is 127.123[mm] long.

A Phase of 37[deg] moves the first Point 127.123 * 37 ∕ 360[mm] along the Path.

The motion at the input to the Path FB moves the first Point relative to this position.

Re-generate Motion-Points button

Click to the Number of Motion-Points parameter.

If you have previously made Pin-Joints with Motion-Points, you must add the Pin-Joints again.


Point List and Data Display 

Motion-Point Information box

Headers: Name | Index | Phase

Name is the name given to identify the Point

If you click on Point in the list it shows as Red in the graphic-area.

Index is the Point number identity
Phase is the relative displacement along the sketch-element, relative to the origin of the fist Point of the sketch-element

Display Data of the First Point as:

Show Nothing - nothing shows above the FB
Show Distance - the absolute distance along the Motion-Path of the first Motion-Point
Show Phase - the relative angle along the Motion of the first Motion-Point. 360 = 1 Path Length

tog_minusLength Control tab - Path Length using Diagram


Path Length using dimension 

You can specify the length of the sketch-path with a 'Controlling Dimension', e.g. for a Belt.

Before you edit the length of the sketch-path, ideally fully defined the sketch-path with constraints and dimensions or the results may be unexpected.

Controlling Dimension [Dimension Name]

The Dimension-Name that controls the length of the sketch-path.

1.Click the Controlling Dimension box

The Part-Editor opens.

2.Click the 'arrowhead' of a dimension

Ideally a Line. [If you click an arc dimension, you will not be able to add a pulley to that arc later].

The dimension will control the total length of the sketch-path.

The dimension cannot be 'grey'.

The Part-Editor closes.

The Dimension-Name you click is now in the Controlling Dimension

Actual Path Length [mm] Read only

Target Path Length [mm] Read / Write box

3.Enter the length of the sketch-path as a target length.

Minimum and Maximum Dimension Value

Set these to limit the range over which the Controlling Dimension can change.

Note: It is best to make the Target Path Length near to the Active Path Length, then, edit the Target Belt Length in small steps with the Spin-Box tool until it equals the Belt Length you want in your design.


 Belt Tooth Pitch 

The Belt-Tooth-Pitch  does not control the belt length.

If you add pulleys, then the number of teeth [See Pulley dialog-box ] and the Belt-Tooth-Path controls the diameter of the pulley.

See also: Pulley dialog-box.

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