IfcSecondProjAxis

Definition from ISO/CD 10303-42:1992: This function returns the normalized vector that is simultaneously the projection of arg onto the plane normal to the vector z-axis and onto the plane normal to the vector x-axis. If arg is NULL then the projection of the vector (0.,1.,0.) onto z-axis is returned.

NOTE Corresponding STEP function: second_proj_axis. Please refer to ISO/IS 10303-42:1994, p.103 for the final definition of the formal standard.

HISTORY New function in IFC Release 2x

EXPRESS specification:

FUNCTION IfcSecondProjAxis

  (ZAxis, XAxis, Arg: IfcDirection)
    : IfcDirection;
LOCAL
  YAxis : IfcVector;
  V     : IfcDirection;
  Temp  : IfcVector;
END_LOCAL;

  IF NOT EXISTS(Arg) THEN
    V := IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,1.0,0.0]);
  ELSE
    V := Arg;
  END_IF;
  Temp  := IfcScalarTimesVector(IfcDotProduct(V, ZAxis), ZAxis);
  YAxis := IfcVectorDifference(V, Temp);
  Temp  := IfcScalarTimesVector(IfcDotProduct(V, XAxis), XAxis);
  YAxis := IfcVectorDifference(YAxis, Temp);
  YAxis := IfcNormalise(YAxis);
  RETURN(YAxis.Orientation);

END_FUNCTION;