FUNCTION nmsf_curve_check

(* SCHEMA aic_non_manifold_surface; *)

FUNCTION nmsf_curve_check (cv : representation_item) : BOOLEAN;  
 
(* This function varifies the validity of a curve in the context of a
   non-manifold surface model. Representation_items are
   valid input, however, they are supposed to be curves; otherwise
   this function will return false.
*)

 (* complex subtypes of curve that are both bounded_curve and
    oneof conic, curve_replica, line, or offset_curve_3d are not
    valid
 *)
 IF SIZEOF (['AIC_NON_MANIFOLD_SURFACE.BOUNDED_CURVE',
   'AIC_NON_MANIFOLD_SURFACE.CONIC',
   'AIC_NON_MANIFOLD_SURFACE.CURVE_REPLICA',
   'AIC_NON_MANIFOLD_SURFACE.LINE',
   'AIC_NON_MANIFOLD_SURFACE.OFFSET_CURVE_3D'] * TYPEOF(cv)) > 1
 THEN RETURN(FALSE);
 ELSE

  (* b_spline_curves shall not self-intersect
   *)
  IF (('AIC_NON_MANIFOLD_SURFACE.B_SPLINE_CURVE' IN TYPEOF (cv)) AND
    (cv\b_spline_curve.self_intersect = FALSE) OR
    (cv\b_spline_curve.self_intersect = UNKNOWN))
  THEN RETURN(TRUE);
  ELSE

    (* conics and lines are valid curve types
     *)
    IF SIZEOF (['AIC_NON_MANIFOLD_SURFACE.CONIC',
    'AIC_NON_MANIFOLD_SURFACE.LINE'] * TYPEOF (cv)) = 1 THEN
      RETURN(TRUE);
    ELSE

      (* a curve_replica shall reference a valid curve
       *)
      IF 'AIC_NON_MANIFOLD_SURFACE.CURVE_REPLICA' IN TYPEOF(cv) THEN
        RETURN (nmsf_curve_check(cv\curve_replica.parent_curve)); 
      ELSE 
 
        (* an offset_curve_3d shall not self-intersect and
           shall reference a valid curve; a polyline is not a
           valid basis_curve
         *)
        IF (('AIC_NON_MANIFOLD_SURFACE.OFFSET_CURVE_3D' IN TYPEOF (cv)) 
          AND
          ((cv\offset_curve_3d.self_intersect = FALSE) OR
          (cv\offset_curve_3d.self_intersect = UNKNOWN))
          AND
          (NOT ('AIC_NON_MANIFOLD_SURFACE.POLYLINE' IN TYPEOF
          (cv\offset_curve_3d.basis_curve)))) THEN
          RETURN (nmsf_curve_check(cv\offset_curve_3d.basis_curve)); 
        ELSE 
 
          (* a pcurve shall reference a valid curve and a valid
             basis_surface
           *)
          IF 'AIC_NON_MANIFOLD_SURFACE.PCURVE' IN TYPEOF(cv) THEN 
            RETURN ((nmsf_curve_check
            (cv\pcurve.reference_to_curve\representation.items[1]))
            AND
            (nmsf_surface_check(cv\pcurve.basis_surface)));
          ELSE 
 
            (* a surface_curve references a curve_3d and one or
               two pcurves or one or two surfaces or one of
               each; all of these references shall be valid
             *)
            IF 'AIC_NON_MANIFOLD_SURFACE.SURFACE_CURVE' IN TYPEOF(cv) THEN 

              (* if the curve reference is correct, check also the rest
               *)
              IF nmsf_curve_check(cv\surface_curve.curve_3d) THEN
                REPEAT i := 1 TO SIZEOF
                (cv\surface_curve.associated_geometry);

                  (* do for one or two associated_geometrys:
                   *)
                  IF 'AIC_NON_MANIFOLD_SURFACE.SURFACE' IN 
                    TYPEOF (cv\surface_curve.associated_geometry[i]) THEN  
                    IF NOT nmsf_surface_check
                      (cv\surface_curve.associated_geometry[i]) THEN  
                      RETURN(FALSE);  
                    END_IF;  
                  ELSE  
                    IF 'AIC_NON_MANIFOLD_SURFACE.PCURVE' IN TYPEOF 
                      (cv\surface_curve.associated_geometry[i]) THEN  
                      IF NOT nmsf_curve_check
                        (cv\surface_curve.associated_geometry[i]) THEN 
                        RETURN(FALSE);  
                      END_IF;  
                    END_IF;  
                  END_IF; 
                END_REPEAT;  
                RETURN(TRUE);
              END_IF; 
            ELSE

              (* a polyline shall have at least 3 points 
               *)
              IF 'AIC_NON_MANIFOLD_SURFACE.POLYLINE' IN TYPEOF(cv) THEN
                IF (SIZEOF (cv\polyline.points) >= 3) THEN RETURN (TRUE);
                END_IF;
              END_IF;
            END_IF; 
          END_IF; 
        END_IF; 
      END_IF; 
    END_IF; 
  END_IF; 
 END_IF; 
 (* FALSE is returned if the input parameter cv is not a valid curve.
  *)
 RETURN (FALSE); 
END_FUNCTION;

Referenced By

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2012-03-27T17:14:00-04:00