FUNCTION IfcFirstProjAxis

(* SCHEMA IFC2X2_FINAL; *)

FUNCTION IfcFirstProjAxis
	(ZAxis, Arg : IfcDirection)
	: IfcDirection;
  LOCAL
    XAxis : IfcDirection;
    V     : IfcDirection;
    Z     : IfcDirection;
    XVec  : IfcVector;
  END_LOCAL;
  
    IF (NOT EXISTS(ZAxis)) THEN
      RETURN (?) ;
    ELSE
      Z := IfcNormalise(ZAxis);
      IF NOT EXISTS(Arg) THEN
        IF (Z.DirectionRatios <> [1.0,0.0,0.0]) THEN
          V := IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([1.0,0.0,0.0]);
        ELSE
          V := IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,1.0,0.0]);
        END_IF;
      ELSE
        IF (Arg.Dim <> 3) THEN
          RETURN (?) ;
        END_IF;
        IF ((IfcCrossProduct(Arg,Z).Magnitude) = 0.0) THEN
          RETURN (?);
        ELSE
          V := IfcNormalise(Arg);
        END_IF;
      END_IF;
      XVec  := IfcScalarTimesVector(IfcDotProduct(V, Z), Z);
      XAxis := IfcVectorDifference(V, XVec).Orientation;
      XAxis := IfcNormalise(XAxis);
    END_IF;
    RETURN(XAxis);
END_FUNCTION;

Referenced By

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2012-03-27T17:20:56-04:00