Function-Block toolbar > Measurement Function-Block (FB)


Function-Block menu (or Toolbar) > Add Measurement Function-Block (FB)


The Measurement Dimension:

measures between sketch-elements, in different Part, as displayed in the Mechanism-Editor.
is a 'driven' dimension by the relative motion of the Parts
shows the dimension in the graphic-area

Dimensions displayed in the graphic area include:

Length of a Line
Distance between: two Points*, a Line and a Point, two parallel Lines
Angle between: two Points*, two Lines, three Points.

The Function-Block:

Has two outputs when the measurement is between two Points
Has one output with all other measurements
Each output-connector gives motion-derivatives of linear and angular dimensions.

How to Add:

1.Click the Measurement FB in the Function-Block Toolbar.
2.Click the sketch-elements between which you want to measure.
3.Click the graphic-area (slowly or two times) to complete the command.

The Measurement FB and the measurement between the sketch-elements show in the graphic-area.

* You can also click the X-axis or Y-axis of a Part as a 'Line'.

How to Use:

In the Mechanism Editor: measure the length*, radius*, distance or angle between sketch-elements in the same or different Parts.

* These would be fixed dimensions and not very useful to know.

You can connect the output-connector(s):

1.To a Graph FB to plot the Linear or Angular Position, Velocity and Acceleration of the Measurement. See Top-Tip below
2.To the input-connector of a Golden FB in another kinematic-chain. The motion-values from the Measurement FB become the independent variable, rather than a Linear-Motion FB.
3.To a Motion-Dimension for a Rocker or Slider. The Rocker or Slider moves with the motion as given by the Measurement FB.

Note: For options 2 and 3: you will see a message in the Feedback area: '1 Mechanism dependencies detected'. You should rebuild the model when the number of dependencies becomes more than 1 if the data is critical, before you use the data for a Cam, for example.

Top-Tip - 1

You can change the motion derivative you display in the Graph by using the Y–axis options.

Top-Tip - 2

To plot the position, velocity and acceleration of a Measurement in the same graph:

1.Drag a wire from the same output-connector of the Measurement FB three times to three different input-connectors on a Graph FB.
2.Use the Y–axis display options in the Graph dialog-box to display all motion derivatives.

Top-Tip - 3

If you only want to know the length of a Line then CTRL -Click the Line and the Element-Properties dialog-box shows.

See also: Tutorial 6.5 ; Element-Properties


See Also:

Function-Block menu

Tutorial 6: Add and Connect 'Golden' Function-Blocks

tog_minusHow to Add a Measurement FB


STEP 1: Click Function-Block menu (or toolbar) > Add Measurement FB

Example Measurement between two Points.

STEP 2: Click sketch-elements in the graphic-area
STEP 3: Click in the graphic-area to place the Measurement FB.

The Measurement FB is at the Base-Part. You can drag the FB to a more convenient location.

In this example:

The dimension4s is between two Points1s-red2s

The Measurement FB3s has two output-connectors when it measures between two Points

The Measurement FB has one output-connector when you measure between any other sketch-elements.

See details below for motion-values available from the output-connectors.

tog_minusLinear Distance

Measurement: Length or Radius

Measurement: Distance: Two Points

Measurement: Perpendicular Distance: Point and Line



Measurement Dimension

Measurement of a Line or Radius of a Circle in the Mechanism Editor

A Line or CAD-Line.

A Circle or Arc.

Length: The length of the Line!

Radius: The radius of the circle or arc.

Measurement between two Parallel Lines in the Mechansim Editor

Two Parallel Lines1s-red2s.


It is often difficult to measure the distance between two parallel lines.

The Measurement FB will often return the angle between the lines as 0º, 360º or 180º.

See Also: Angle Measurement between Two Lines, and Distance between Line and Point.

Measurement FB

Two Points1s-red2s

Distance between two Points.

The Measurement FB has two output-connectors:

The top output-connector gives the gap, the rate-of-change of the dimension and the second rate-of-change of the dimension
The bottom output-connector gives the angle, angular velocity and angular acceleration between the Points.


A Point and a Line

Perpendicular Distance between a Line and a Point.

Select the Point first, then the Line.

You many need to add a Line to a Part in the Part-Editor.

To measure a 'Horizontal Distance' or a 'Vertical Distance' you may need to add a Line to a Part in the Part-Editor.

tog_minusAngle between Three Points

My work-around when two Points are at one Point, but I want to add a measurement with the Point at the apex of an angle.

1.Edit the Part and add a 'Free' Line so that its start-Point is near to the coincident Points.
2.Add the Measurement: Three Points with the Points at each end of the Line, plus another Point.

When you do this, the angle is not yet giving the angle you actually want.

3.Edit the Part to make one of the Points at the end of the Line to be coincident with the Point you want to be the apex of the angle.

Now, the angle is the angle you want.

Measurement: Angle between Three Points

In the graphic-area:

1.Click a Point '1'.

Point '1' is the 'apex' of the angle.

2.Click  Point '2'
3.Click Point '3'.

The Measurement FB displays the counter-clockwise angle from Point '2' to Point '3'.



Measurement Dimension


Three Points

1.Click Point 1s-red

The apex

2.Click Point 2s
3.Click Point 3s

Internal Angle

Points two to three in a Counter-Clockwise direction.


Three Points

1.Click Point 1s-red

The apex

2.Click Point 2s
3.Click Point 3s

External Angle

Points two to three in a Counter-Clockwise direction.

tog_minusAngle between Two Lines

Measurement: Angle between Two Lines


After you select the two Lines, and before you click in the graphic-area to place the dimension, you can move you mouse around the apex of the angle to control which angle to display. There are eight possible angles:

If you move your mouse pointer 'counter-clockwise' around the apex of the two Lines, MechDesigner shows:

The angle that is less than 180° for the four angle possibilities

Acute, Obtuse, Supplementary and Vertical angles

If you move your mouse 'clockwise' around the apex of the two Lines, MechDesigner shows:

The four angles that are the 'reflex' angles to the others.

Help Files for MechDesigner and MotionDesigner 11.1 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd