More About Dimensional/Geometrical Constraints

There are a few things that you need to know about the Constraint command..

When using Constraint, keep in mind the following:

• A Projection/Intersection edge created by a constraint is hidden till the software detects a problem with this constraint. In this case, it appears to indicate the error.
• When creating a coincidence constraint between a point in the current sketch and a 3D element outside the sketch, by default the constraint is created on the projection of this 3D element whenever possible. (The constraint is created on the intersection of this 3D element with the sketch plane only when there is no projection for the 3D element.) So if you want to create a constraint on the intersection of the 3D element with the sketch plane, you need to create an intersection between this 3D element and the sketch plane, and then create the coincidence constraint with the intersected point.
• We recommend not to create constraints or projections from wireframe elements which lie on a plane orthogonal to the sketch. As a matter of fact, the orientation of the result of these projections in the sketch plane is not stable. (Constraints with external elements use projection first).
• You can also define constraints using Constraint Definition dialog box , or by means of contextual commands.
• You can refer to Selecting Using a Filter and Selecting Using Other Selection... Command in the Infrastructure User's Guide to help you select the elements that you want to constrain.

The Shift key lets you deactivate a constraint (auto-detected via SmartPick).