8.9.6.4 IfcBuildAxes（构建轴）

8.9.6.4.1 语义定义（Semantic definition）

8.9.6.4.2 形式化表示（Formal representation）

FUNCTION IfcBuildAxes
  (Axis, RefDirection : IfcDirection) 
    : LIST [3:3] OF IfcDirection;
LOCAL
  D1, D2 : IfcDirection;
END_LOCAL;
  D1 := NVL(IfcNormalise(Axis), IfcRepresentationItem() || IfcGeometricRepresentationItem () || IfcDirection([0.0,0.0,1.0]));
  D2 := IfcFirstProjAxis(D1, RefDirection);
  RETURN ([D2, IfcNormalise(IfcCrossProduct(D1,D2))\IfcVector.Orientation, D1]);

END_FUNCTION;

8.9.6.4.3 参考文献

IfcAxis2Placement3D