Registers a routine for creating a cliff blend. This allows you to
register a routine into the Open API environment for the cliff
blend.

To register a routine named cliff_routine(), the call is:
UF_MODL_register_cliff_blend(cliff_routine)

where cliff_routine is defined as:
int cliff_routine(tag_t obj_id, int cliff)

Internal and External

Typedef for a rpo routine function pointer.

Typedef for a UDF mapping routine function pointer.

Registers a routine for creating a variable radius blend (VRB). This
allows you to register a routine into the Open API environment
so that you can specify the points necessary for the VRB.

Subsequently, every time a blend is created, this registered routine is
called. Note that this routine works in conjunction with
UF_MODL_create_blend. The general procedure for using this
function is to:

1. Register the vrb_routine with a call to UF_MODL_register_var_blend.
2. Create the variable blend with a call to UF_MODL_create_blend. Your
registered routine is called once for each edge on the list that
was inputted to UF_MODL_create_blend.
3. Unregister your vrb_routine with a call to UF_MODL_unregister_var_blend.

To register a routine named vrb_routine(), the call is:
UF_MODL_register_var_blend(vrb_routine)

where vrb_routine is defined as:

int vrb_routine(tag_t obj_id, double points[100][3],
char radii[100][256],
int smooth_overflow, int cliff_overflow,
int notch_overflow, int number_pts)

The integer values for smooth_overflow, cliff_overflow, and
notch_overflow control the overflow during blending. The following
string defined constants should be used.

UF_MODL_BLEND_NO_OVERFLOW - allows overflow control.
UF_MODL_BLEND_SMOOTH_OVERFLOW - does not allow smooth overflow control.
UF_MODL_BLEND_CLIFF_OVERFLOW - does not allow cliff overflow control.
UF_MODL_BLEND_NOTCH_OVERFLOW - does not allow notch overflow control.

vrb_tol allows you to specify a variable radius blend tolerance and it
should be positive and bigger than 10E-8mm.

Internal and External

Refer to example