IFC 4.3.0.1 (IFC4X3) development

# 8.9.3.26 IfcCurveBoundedPlane

## 8.9.3.26.1 Semantic definition

The IfcCurveBoundedPlane is a parametric planar surface with curved boundaries defined by one or more boundary curves. The bounded plane is defined to be the portion of the basis surface in the direction of N x T from any point on the boundary, where N is the surface normal and T the boundary curve tangent vector at this point. The region so defined shall be arcwise connected.

The BasisSurface is an IfcPlane that establishes the position coordinate system by SELF\IfcElementarySurface.Position. The OuterBoundary and the InnerBoundaries (if provided) shall lie on the surface of IfcPlane. The outer and inner boundary curves shall be defined using the u, and v values provided by parameterization of the BasisSurface as their x, and y coordinate values.

## 8.9.3.26.4 Formal representation

ENTITY IfcCurveBoundedPlane
SUBTYPE OF (IfcBoundedSurface);
BasisSurface : IfcPlane;
OuterBoundary : IfcCurve;
InnerBoundaries : SET [0:?] OF IfcCurve;
END_ENTITY;