Frequently, a design has more than one Pin-Joint at the same position, which join together more than two Parts.

The rules to add coincident Pin-Joints, explained below, become important when you need to also add Motion-Dimension FBs to specify the motions of one or two(2) of the Parts at the Pin-Joint.

Example:

We want to join Points(1,2,3) that are in Parts(1,2,3) with Pin-Joints(1,2) at one position.

Pin-Joint#1 is between Points 1 & 2 (in Parts 1 & 2)

Then, Pin-Joint#2 has two(2) options:

Option A: Pin-Joint#2 is between Points 3 & 1 (in Parts 3 & 1)

- or -

Option B: Pin-Joint#2 is between Points 3 & 2 (in Parts 3 & 2)

When to do Option A or Option B becomes important when you need to also add Motion-Dimension FBs to specify the motions of the two(2) Parts.

Preparation example:

STEP 1:Add Pin-Joint #2

We have clicked a total of three(3) Points.

•One Point at

•Two Points at

However, the Pin-Joint is between two(2) Points.

Therefore, there is ambiguity as to which two(2) Points you want for the Pin-Joint.

Ambiguity: when MechDesigner is not sure which element to select.

Select-Elements dialog-box

STEP 2:Select the Points in the Select-Elements dialog-box:

Which two Points do we select from the three Points?

There are three ways to select two(2) elements from three elements

•You can select Point11 and Point5

- or -

•You can select Point11 and Point7.

However, you cannot select Point5 and Point7.

Why? Because Point5 and Point7 are joined with a Pin-Joint, already.

Note: the word 'not' the image to the left, at the bottom of the dialog

STEP 2:To confirm again, select the Points:

The Select-Elements dialog-box closes.

The Points move together to add the Pin-Joint.

Top-Tip: