Concentric Constraint

In this Task

• Concentric constraints will be applied so that the inner circles are concentric to the outer arcs.

Associated Tasks

• Inserting a Point into the center of an arc.
• Making the point concentric to the arc. This is done so that a dimension can be inserted using the vertex of the point.

Before you Start

• The order in which the concentric objects is selected is important.

Take Note

• Dimensional constraints can only be inserted using vertex points. Center points, midpoints etc cannot be used.
• Menu options for the Default menu and workspace, the Ribbon and Palettes are provided directly under the Command Name heading.

 

Concentric Constraint

Ribbon : Insert | Constraint | Concentric

Default Menu : Constraints | Concentric

Palette : Sketch | Constraints | Concentric

The Concentric constraint fixes concentricity between 2 circles or arcs.Concentricity is maintained when the circles are moved or modified.A Concentric constraint symbol is inserted to indicate a concentric relationship.

 

The circles will be made concentric to the outer arcs shown in the illustration below.

Circles will be made concentric to outer arcs

Select the Concentric Constraint tool, then select the top circle first, then the top outer arc, shown below.

Select the circle, then the arc

Repeat this for the lower circle and arc. The result is shown below with the Concentric constraint marker shown by the arrow.

Circles made concentric to the outer arcs

 

Inserting a Point

Ribbon : Draw | Draw 2D | Point | Cross

Default Menu : Draw | Point | Cross

Palette : Sketch | Point | Cross

This tool is useful for marking centers of arcs and circles prior to dimensioning.The overall length of the Point markers can be adjusted using the Selection Info palette.

So that dimensional constraints can accurately dimension the center point of a circle, a point must be inserted. The inserted point must then be made concentric to its associate circle.

Right click onto the Point tool and make the size approximately 15. This point can be inserted onto the CL layer if preferred.

Using the Center snap, insert the point onto the center of the arc shown below.

Insert a point onto the center of the arc

Make the newly inserted point concentric to the arc using the Concentric constraint. Select first the point, then the arc, shown above.

Take Note

When dimensioning to the center of the arc, the vertex snap mode should be used.