Adding constraints to a sketch helps you finalize the shape of a sketched feature. Abaqus/CAE can apply constraints to your sketch automatically. You can use the sketcher options to select the types of constraints that Abaqus/CAE can add to the sketch. (For more information, see “Customizing the use of constraints in the Sketcher,” Section 20.9.10.)
To constrain a sketch automatically:
From the tools in the Sketcher toolbox, select the auto-constrain tool 
. For a diagram of the tools in the Sketcher toolbox, see “The Sketcher tools,” Section 20.4.1.
Abaqus/CAE displays prompts in the prompt area to guide you through the procedure.
Select the entities to be constrained.
Note: You can select the entire sketch; Abaqus/CAE will not duplicate any existing constraints.
Click Done in the prompt area.
Abaqus/CAE creates the constraints on the sketch. Sketch modification tools such as translate, rotate, scale, and mirror can override constraints.
If desired, use the Delete tool to remove any unwanted constraints. For more information, see “Deleting Sketcher objects,” Section 20.19.4.
