Prepare the model so that these elements have these properties.

Preparation example:

•Pin-Joint

•The Points at Pin-Joint are at the ends of Lines.

•Lines in two different Parts that radiate from two Points

•Part is a kinematically-defined Part (Green Part-Outline).

•Part is a free Part (Blue Part-Outline)

Kinematic FB toolbar > Motion-Dimension FB (right of Graphic-Area >>)

Element #1: PIN-JOINT

The Pin-Joint is a joint between two Parts, and:

•One Part is a kinematically-defined Part

•One Part is a free Part

Elements #2 and #3: LINES

Each Line must be a child to a Point that is also a child to the Pin-Joint. (Element #1)

•Element #2: a Line in the kinematically-defined Part

•Element #3: a Line in the free Part

Click in the Command-Manager

Result: a Rocker

A Motion-Dimension FB to specify the angle between Lines, Elements #2 and #3

The dimension is an Orange color in the graphic-area.

Kinematics-Tree for a Rocker

When we add a Motion-Dimension FB to a Pin-Joint, we identify it as a Rocker in the Kinematics-Tree.

The kinematic elements are:

•'Part' + 'Pin-Joint' + 'Motion-Dimension' = 'Rocker'

Prepare the model so that these elements have these properties.

Preparation example:

1.Two Parts  

One is a kinematically-defined Part (Green Part-Outline)...the Base-Part

The other is a free Part (Blue Part-Outline)

2.The Parts are Joined... with a Slide-Joint

Note the Points are the start-Points and end-Points of the Lines that are selected for the Slide-Joint

Kinematic FB toolbar > Motion-Dimension FB (right of Graphic-Area >>)

Element #1: SLIDE-JOINT

The Slide-Joint is a joint between two Parts, and:

•One Part is a kinematically-defined Part

•One Part is a free Part

Elements #2 and #3: POINTS

Each Point must be a child to a Line that is also a child to the Slide-Joint. (Element #1)

•Element #2: a Point that is a start-Point or end-Point of a Line in the kinematically-defined Part

•Element #3: a Point that is a start-Point or end-Point of a Line in the free Part

Click in the Command-Manager

Result: a Slider

The Motion-Dimension FB to specify the linear distance between Points, Elements #2 and #3

All Parts are now kinematically-defined Parts

The dimension is a Gold color.

Kinematics-Tree

When we add a Motion-Dimension FB to a Slide-Joint, we identify it as a Slider in the Kinematics-Tree.

The kinematic elements are:

•'Part' + 'Slide-Joint' + 'Motion-Dimension' = 'Slider'

There are two Parts and a Line in the Base-Part - three Parts in total.

The Points at the ends of the lines are 5, 7 and 11.

In the image to the left, we have joined Point7 to Point5 with the first Pin-Joint.

Now we must add a second Pin-Joint.

PROCEDURE 1

We will add the second Pin-Joint between Point11 and Point5.

Q: Why Point5 and not Point7?

A: Point5 is a child to the horizontal Line .
We want two Motion-Dimensions to reference the same horizontal Line .

To add the Pin-Joint: select Point11 and then try to select Point5.

Because Point5 and Point7 are at the same position, MechDesigner does not know which Point you want to select.

There is ambiguity between Point5 and Point7. Hence, the Select Elements dialog-box opens.

The Select Elements dialog-box:

•Gives ALL of the elements to complete the command are available

•The element you had selected first is at the top of the list.

•None of the elements are selected.

CTRL + Click ALL of the elements you need to complete the command.

In this image, we select Point 11 and Point5

1.CTRL + CLICK Point11 AND Point5

2.Click

Now, the each Part is joined with a Pin-Joint to the Point at the left end of the Line in the Base-Part.

The two Parts are now joined to the Base-Part with two Pin-Joints

Now, use the Motion-Dimension FB two times

1.Click Function-Block toolbar > Add Motion-Dimension FB.

The Command-Manager show that we must select three elements , and .

The first-element must be a Pin-Joint or Slide-Joint.

We have two Pin-Joints!

When we click the Pin-Joints in the graphic-area the Select-Elements dialog-box opens as there are two Pin-Joints.

In the Select-Elements dialog box:

Click the Pin-Joint5 - the one with the lower Element-Number if the names are different to those in the image.

Now we must select two Lines.

Click the horizontal Line as the second element

Click the CAD-Line along one the Parts with which the Pin-Joint is made.

This image shows the three elements in the Command-Manager boxes.

The first Rocker Motion-Dimension FB.

Now, add the second Motion-Dimension FB

We must now select another three elements,

Select Function-Block Toolbar > Motion-Dimension FB in the  again.

These are the elements.

Joint: Pin-Joint2.

Now, there is not ambiguity. There is only one Pin-Joint available.

Line – Solved: select the horizontal Line.

Line – Free: select the CAD-Line along the center of the Blue Part.

Here, you can see the result.

Both Motion-Dimensions FBs use the Horizontal Line in the Base-Part as a reference for the motion-dimension.

Note: When you add two Motion-Dimensions, the FBs may be on top of each other.

Drag each FB so you can see them.

Again, there are two Parts and a Line in the Base-Part.

The Points at the ends of the lines are 5, 7 and 11.

We want to:

•Add a Pin-Joint between 'Point7' and 'Point5', and

•Add a Pin-Joint between 'Point11' and 'Point7'.

In the image to the left, Point7 is joined to Point5

CONDITION 2

Add the second Pin-Joint between Point11 to Point7.

•Q: Why Point7 and not Point5 ?

•A: Because Point7 is a child to CAD-Line and we want this Motion-Dimension to reference CAD-Line.

•We do not want the Motion-Dimension to reference the Line in the Base-Part. That was Procedure 1, above.

Select Point11.

Then try to select Point7

There is ambiguity between Point5 and Point7. Hence, the Select Elements dialog-box opens.

•ALL the elements you need for the command are made available to you

•The first element you select is at the top of the list.

In the image to the left, we have selected Point11 and Point7.

1.CTRL + CLICK Point11 AND Point7

2.Click 'OK'

The two Parts become joined with a Pin-Joint.

To add two Motion-Dimension FBs, use Add Motion-Dimension FB two times.

The Add Motion-Dimension FB requires three elements.

Element 1: A Joint.

There is ambiguity when we select the Pin-Joint, hence the Select Elements dialog-box opens.

Here, I have selected the first Pin-Joint  at the top of the list.

Then, Click 'OK'.

Elements 2 & 3: Two Lines – a Solved Line then a Free Line

There are three Lines to select from.

Select the Horizontal Line and the CAD-Line along one of the Parts

The three elements in the Command-Manager

Click in the Command-Manager

You can see the First Motion-Dimension FB.

Add the second Motion-Dimension.

We must now select another three elements,

These are the elements:

1.Joint: when we select the Pin-Joint4, there is no ambiguity because the existing Motion-Dimension FB uses the other Pin-Joint.

You must select this line because the Pin-Joint4 uses Point7 on this Line.

2.Line – Free: select the CAD-Line along the center of the Blue Part.

This image shows the end result.

First Motion-Dimensions FB: uses the Horizontal Line that is a child to the Base-Part as a reference Line.

Second Motion-Dimension FB: uses the CAD-Line along the center of the added Part that is kinematically-defined by virtue of the First Motion-Dimension FB - see Procedure 1

Note: When you add two Motion-Dimensions, the FBs may be on top of each other.

DRAG each FB so you can see them.

A Slider

To add a Motion-Dimension FB (for a Slider) you must select a Slide-Joint, and then one Point from each of the two Lines that define the Slide-Joint.

•The properties of the Motion-Dimension FB are determined by the properties of the Slide-Joint.

•The properties of the Slide-Joint are determined by the properties of the Lines you select to add the Slide-Joint.

•The properties of the Lines are determined by the properties their start-Points and end-Points.

Therefore, the positive-direction of the Motion-Dimension is defined by the start-Point and end-Point of the two Lines in the Slide-Joint.

If the positive-direction of the Motion-Dimension is not as you want, you will need to add the Slide-Joint, and the Lines again.

Always, the positive-direction of a Motion-Dimension for a Slider :

'...the positive direction of the Line, or CAD-Line, that is kinematically-defined before you add the Motion-Dimension FB to the Slide-Joint.

What is the Positive-Direction of a Line, CAD-Line, or Part?

The direction in which you drag - from its start-Point to its end-Point - when you add the Line, CAD-Line, or Part.

Example Sliders

•Line 1 is Green Part – it belongs to a kinematically-defined part.

•Line 2 the Free Blue Part – it becomes a Slider after you add the Motion-Dimension FB

I have used the red arrow-heads to show the direction in which I 'dragged' to add the Lines and Parts

•Line 1 – L1-  Drag to the right

•Line 2 – L2 - Drag to the right

The Motion-Dimension is 39.14.

Increasing the value, will move the Slider to the right.

The small Green arrowhead at the start-Point of Line 1 shows the positive direction of the Line and the Slider.

•Line 1 – L1 - Drag from Left to the Right

•Line 2 – L2 - Drag from Right to the Left

The Motion-Dimension is '20'.

Increasing the value, say to 36, will move the Slider to the right.

The small arrowhead shows the positive direction

•Line 1 – L1 - Drag from Right < Left

•Line 2 – L2 - Drag from Left > Right

The Motion-Dimension is -20'.

Increasing the value, say to -6, will move the Motion-Part(Slider) to the left.

The small arrowhead shows the positive direction

•Line 1 – L1 - Drag from Right to Left

•Line 2 – L2 - Drag from Right to Left

The Motion-Dimension is -20'.

Increasing the value, say to -6, will move the Motion-Part(Slider) to the left.

The small arrowhead shows the positive direction.