8.9.6.12 IfcGetBasisSurface

8.9.6.12.1 Semantic definition

8.9.6.12.2 Formal representation

FUNCTION IfcGetBasisSurface
(C : IfcCurveOnSurface) : SET[0:2] OF IfcSurface;

  LOCAL
    Surfs : SET[0:2] OF IfcSurface;
    N : INTEGER;
  END_LOCAL;

  Surfs := [];
  IF 'IFC4X3_ADD2.IFCPCURVE' IN TYPEOF (C) THEN
    Surfs := [C\IfcPCurve.BasisSurface];
  ELSE
    IF 'IFC4X3_ADD2.IFCSURFACECURVE' IN TYPEOF (C) THEN
      N := SIZEOF(C\IfcSurfaceCurve.AssociatedGeometry);
      REPEAT i := 1 TO N;
      Surfs := Surfs + IfcAssociatedSurface(C\IfcSurfaceCurve.AssociatedGeometry[i]);
      END_REPEAT;
    END_IF;
  END_IF;
  IF 'IFC4X3_ADD2.IFCCOMPOSITECURVEONSURFACE' IN TYPEOF (C) THEN

    (* For an IfcCompositeCurveOnSurface the BasisSurface is the intersection of the BasisSurface of all the segments. *)

    N := SIZEOF(C\IfcCompositeCurve.Segments);
    
    IF ('IFC4X3_ADD2.IFCCURVESEGMENT' IN TYPEOF(C\IfcCompositeCurve.Segments[1])) THEN
      Surfs := IfcGetBasisSurface(C\IfcCompositeCurve.Segments[1]\IfcCurveSegment.ParentCurve);
    END_IF;
    IF ('IFC4X3_ADD2.IFCCOMPOSITECURVESEGMENT' IN TYPEOF(C\IfcCompositeCurve.Segments[1])) THEN
      Surfs := IfcGetBasisSurface(C\IfcCompositeCurve.Segments[1]\IfcCompositeCurveSegment.ParentCurve);
    END_IF;
    
    IF N > 1 THEN
      REPEAT i := 2 TO N;       
        IF ('IFC4X3_ADD2.IFCCURVESEGMENT' IN TYPEOF(C\IfcCompositeCurve.Segments[i])) THEN
          Surfs := Surfs * IfcGetBasisSurface(C\IfcCompositeCurve.Segments[i]\IfcCurveSegment.ParentCurve);
        END_IF;
        IF ('IFC4X3_ADD2.IFCCOMPOSITECURVESEGMENT' IN TYPEOF(C\IfcCompositeCurve.Segments[i])) THEN
          Surfs := Surfs * IfcGetBasisSurface(C\IfcCompositeCurve.Segments[i]\IfcCompositeCurveSegment.ParentCurve);
        END_IF;
      END_REPEAT;
    END_IF;
  END_IF;
  RETURN(Surfs);

END_FUNCTION;

8.9.6.12.3 References

• IfcCompositeCurveOnSurface
• IfcSurfaceCurve