Constraints

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Constraints

Part-Editor - Constraints Menu and Toolbar

In the Part-Editor use the Constraints menu and toolbar to add Constraints,

You can add Constraints

oto a sketch-element

obetween two sketch-elements

obetween a sketch-element and the X-axis or Y-axis

You cannot OVER-constrain a sketch-element. See below: Why cannot I add another Constraint?

See also: Geometry menu and toolbar

Part-Editor: Constraints menu

MD-Menu-Constraints

Part-Editor: Constraints Toolbar

Part-Editor > Constraints toolbar is to the RIGHT of the graphic-area.

MD-TOOLBAR-CONSTRAINTS-2

How to Delete a Constraint

You cannot see Constraints in the graphic-area.

To DELETE a Constraint, you must show it in the Selection-Window.

1.SHIFT+CLICK a sketch-element

OR

1.SHIFT-Click a Point, start-Point, end-Point, or a center-Point

ALL Constraints that you have applied to the sketch-element or Point are now in the Selection-Window.

In the Selection-Window:

2.Right-click the Constraint

In the contextual-menu:

3.Click Delete element.
btn_delkeywordAbout Merge-Points and Coincident Constraint between Points

Add MERGE-POINTS removes a Point*

Usually, use Merge-Points to make a sketch-path or sketch-loop.

You can NOT delete Points* that are Merged.

Add Coincident Constraint (between two Points*) does not delete a Point*.  

Usually, use Coincident-Constraints for construction geometry.

You can delete a Coincident-Constraint to move the Points* again - see How to delete a constraint.

* Points are Points and also start-Points, end-Points, center-Points.
btn_delkeywordWhy can I NOT add a new Constraint?

1.You cannot over-constrain a sketch-element in the Part-Editor

For example: A Point has 2 degrees-of-freedom (DOF).

STEP 1: You can add a Coincident Constraint between a Point and a Line,

The Point can slide along the Line. It now has 1 DOF .

STEP 2: You cannot now add a new constraint between the same Point and the start-Point or end-Point of the Line.

Why: Because a constraint between a Point and a Point would need to 2 DOF. But, the Point only has 1 DOF.

To add a constraint between a Point and a Point, you must remove all other constraints- see How to delete a Constraint.

2.The sketch-element may be too far away from solving the constraint.

For example:

Add Equal constraint to two Lines when their lengths are very different.