Sketch-Loop [a derived name]: A Sketch-Loop is a closed chain of sketch-elements. The sketch-elements are added end to end , with all Points as Merged-Points* [see below] A sketch-loop is NOT an element. It is a derived name.

Profile and Extrusions [and Hole]: We add a Profile to a sketch-loop. We add a Hole through a Profile. The hole must be sketch-loop inside the sketch-loop that defines the shape of the Profile.

Auto-Profile: a sketch-loop is added to the Part automatically, and the Auto-Profile is added to the sketch-loop automatically. These sketch-loop have simple shapes that surround the Joints in each Part. The sketch-elements cannot be used for joints themselves.


When a Point at the end of one sketch-element becomes the same Point at the end of a different sketch-elements, then the two Points have become Merged-Points.

To confirm that two Points have become Merged-Points, click the Point, to see only ONE Point in the Selection-Window. If you see two Points, then it is not a sketch-loop. Use Merge-Points in the sketch-editor to combine the Points into one Point.

There is a special tool in the Part-Editor called 'Merge-Points' to force two Points to become one Point.

These are NOT Sketch-Loops

When you merge three or more Points as one Point – this is a Branch Point
When the sketch-elements cross each other - this is a Figure-of-Eight
When the sketch-elements touch each other to give 'zero' thickness between two sketch-elements.

Example Sketch-Loops


1: A Circle

The simplest sketch-loop.

Useful for a Cam-Follower Roller.

See Also: Cam-Follower

Tutorial 4



2: Lines

A general polygon.


3: Lines and Arcs

General Shape.


4: Arcs and Arcs

General 'free-form' shape

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