DELFAS ( faces, nopts, optdta, bodys, nbodys, sbodys, ifail )
=============================================================

  Delete faces from body

Receives:
  KI_tag_list_face         *faces          --- face(s) to be deleted
 <KI_int_nitems>           *nopts          --- number of actions in 'optdta'
  KI_cod_sllo               optdta[nopts]  --- type of action to mend wounds
                                           ---   SLLOCP => cap
                                           ---   SLLOGR => grow only
                                           ---   SLLOGS => allow shrinkage
                                           ---   SLLORB => leave rubber
                                           ---   SLLOLT => loops together
                                           ---   SLLOLI => loops independent

Returns:
  KI_tag_list_body         *bodys          --- remaining body(s)
  KI_int_nitems            *nbodys         --- number of bodies
  KI_tag_list_int          *sbodys         --- state(s) of the body(s)
                                           ---   RTLOOK => Valid
                                           ---   RTLONG => Negated
                                           ---   RTLOSX => Self-Intersecting
  KI_cod_error             *ifail          --- failure code

Specific errors:
  KI_wire_body              Unable to delete faces from wire body
  KI_all_faces_in_body      Cannot delete all faces in body
  KI_cant_heal_wound        Can't heal wound - impossible geometry
  KI_non_manifold           Cannot heal wound with non-manifold boundary
  KI_not_in_same_shell      Faces not all from the same shell
  KI_not_in_same_part       Faces not all from the same body
  KI_unsuitable_entity      Mixed body
  KI_general_body           general body unsuitable for sweep

Description:
  The faces, which must belong to the same body, are deleted from the body. The
  faces must not form the shell of a sheet body (in this case DELENT should be
  used) but may form an inner shell (ie void) of a solid, in which case that
  shell is deleted. Rubber faces may be deleted from the body but the edges and
  faces around the wound must have geometry attached.

  Any holes left by deleting the faces are healed according to the action code.
  If the action is "cap" then for each hole a new face is created and a surface
  found which fits all the edges of the hole.  If the action is "grow only" the
  faces around the hole are extended until the hole is covered. Edges of faces
  adjacent to a wound which do not form part of the loop of edges around the
  wound, but have a vertex on it, will not be allowed to contract back from that
  point. If the "shrinkage" option is selected, the faces around the hole will
  be allowed to contract if a solution which extends the faces is not found
  first. If the action is "leave rubber" each hole is 'covered' by a rubber
  face.  One of the actions "cap", "grow only", "shrinkage" or "leave rubber"
  must be supplied.

  If the option "loops independent" is selected then each closed loop
  around a face or group of faces is healed independently. The default is to
  "heal loops together".   Healing loops independently can result in a
  fragmented body.

  In general this procedure may give rise to self-intersecting object
  boundaries which could cause unpredictable errors later.

  If local checking is on (see SEINTP and OUINTP), and the action is not leave
  rubber, consistency checks will be made on newly created topological and
  geometrical entities, and the state of the body returned. A state of RTLOOK
  indicates the body is valid. A state of RTLONG indicates that the result body
  was originally "inside out" but has been negated, and is now "positive" (has
  positive volume) and valid. A state of RTLOSX indicates the body is
  self-intersecting and further modelling operations on it may fail. It is the
  responsibility of the calling routine to make any necessary reparation.

  If the session parameter for local checking is switched off or the action is
  "leave rubber", the state returned will be RTLOOK regardless.

  A self-intersecting body can be returned even if the ifail is zero.

  This function is not supported for faces on general bodies.