Before you Begin


What Is a Constraint?

A constraint is a kind of relationship that lets you specify explicitly how the geometry should behave. In other words, if you modify the geometry afterwards via the geometry itself, these relations will be taken into account.

In the Interactive Drafting workbench, you can create geometrical constraints. Geometrical constraints set a relationship that forces a limitation between one or more geometrical elements. The various geometrical constraints are the following:

  • support lines and circles
  • alignment
  • parallelism
  • perpendicularity
  • tangency
  • concentricity
  • horizontality
  • verticality
  • fix
  • middle point
  • equidistant point
  • symmetrical


In the Interactive Drafting workbench, dimensional constraints do not exist as such. It is by creating driving dimensions that you can drive constrained geometry.
It is impossible to modify the definition of a geometrical element (via the Definition dialog box) in a view which contains inconsistent or over-constrained geometry. In such a case, you first need to solve the inconsistencies or remove the extra constraints, and you will then be able to modify the definition of the geometrical element.

What Does Creating Constraints Mean?

You can create constraints using the:

Tools toolbar:

  • Via Autodetection, if you activate the Create Detected Constraints command to automatically create detected constraints.

Visualization toolbar:

  • Explicitly, via the existing Show Constraints command (detected constraints).