2012

You can apply geometric constraints to 2D geometric objects only. Objects
cannot be constrained between model space and paper space.
Specify Constraint Points
With some constraints, you specify constraint points on objects instead of
selecting the objects. This behavior is similar to that of object snaps, but the
locations are limited to endpoints, midpoints, center points, and insertion
points.
For example, a coincident constraint can restrict the location of the endpoint
of one line to the endpoint of another line.
The following glyph is displayed on the object as you roll over the object.
You use this glyph to confirm whether you are specifying the intended point
to constrain.
The fix, horizontal, and vertical constraint icons indicate whether the
constraints are applied to an object or a point.
ObjectPointConstraint
Fix
Horizontal
Vertical
The symmetric constraint icons indicate whether it identifying a symmetrical
point or object, or the symmetrical line.
LineObjectPointConstraint
Symmetric
Apply or Remove Geometric Constraints | 721