Edit a sketch-path or sketch-loop

A Sketch-Loop is a sketch that does not have breaks and the Points that join the sketch-elements are merged into one Point.

Generally, do not make a sketch-loop unless you intend to add to it a Profile/Extrusion (Solid) or a Motion-Path FB.

*About Merge-Points

Each Line or Arc you add to the graphic-area has a Point at each end.

In the Part-Editor, you have two options when you want the ends of two sketch-elements to move to the same position. You can:

make the Points coincident with Constraints toolbar > Add Coincident

- or -

merge the Points with Geometry toolbar > Merge-Points

In each case, the two Points show in the graphic-area as one Point. However:

Add Coincident Constraint does not remove a Point.
Add Merge-Points removes one Point

Why Merge-Points?

Use Merge-Points when you want to make an open or closed sketch-path.

You can use a sketch path for a Motion-Path FB

You can use a closed sketch-path (sketch-loop) for a Profile element.

tog_minus        Sketch-Loops with the Hover Technique and Merge-Points Tool

There are two ways to merge two Points into one Point:

Dynamically, as you add the sketch-elements, with the Hover Technique
Later, after you add the sketch-elements with Geometry toolbar > Merge-Points.

Video of Hover Technique and Merge-Points tool

Using the Merge-Points tool and Hover Techniques

tog_minusWhy do Sketch-Loops fail?

Condition 1: Coincident Points, and not Merged

Points are not recognized as part of a sketch-loop when they are coincident.

You must merge the Points into one Point where each Line and Arc join.

Condition 2: Branches

You CANNOT merge three Points into one Point - for example, the ends of three Lines or Arcs - you have a 'Branch-Point'. A Branch-Point is not O.K.

You CAN merge two Points, then make a different Point become Coincident. This is NOT a Branch-Point.

Condition 3: Figures=of-Eight

A sketch-element can not cross another sketch-element in the same sketch-loop.

A sketch-element cannot osculate, or touch, another sketch-element in the same sketch-loop.

tog_minusExample sketch-loops

Video of Hover Technique and Merge-Points tool

Video of Sketch-Loops

SketchLoop-circle

Circle

The Circle is a sketch-loop. A Circle is frequently used for a Cam-Follower.

SketchLoop-lines

Lines

Lines joined, with Points merged.

SketchLoop-line-arcs

Lines and Arcs

Lines and Arcs, with Points merged.

SketchLoop-arcs-arcs

Arcs and Arcs

Arcs and Arcs, with Points merged.

 

Tutorials and Reference Help Files for MechDesigner and MotionDesigner 14.2 + © Machine, Cam, Mechanism, and Motion Design Software by PSMotion Ltd