The Geometric Expressions routines allow you to reference certain
geometric properties as constraints for defining parameters of
features. For example, you can use the minimum distance between
two objects as a driving expression for the length of a block.
The routines enable you to create the following new types of
expressions:
. Length expression - an expression based upon the length of a curve
or an edge.
. Distance expression - an expression based upon the minimum distance between
two objects, or between a point and an object, or between two points.
. Angle expression - an expression based upon the angle between two objects.

These expressions are created using scalar smart objects (see uf_so.h),
are created as features, and participate in the modeling update.

Many of these routines have an input which is a transformation
(xform). To create this transform and get its tag use the function
UF_SO_create_xform_assy_ctxt which provides the
transform for interpart geometric expressions (or one part occurrence
to another in an assembly tree). If both objects are in the same part,
then the tag of this transform is NULL_TAG.

All input objects to the routines must not be occurrence tags.

The type definitions and enums for the Open API interface to the GEXP module.