This .NET class wraps the AcGeClipBoundary2d ObjectARX class. 

This class defines a planar clipping object for clipping arbitrary 2D polygons or polylines to 2D convex open or closed polyline curves or rectangles. The implementation is similar to the Sutherland-Hodgman pipeline clipping algorithm. 

Detailed edge information can optionally be generated to track the source of each clipped output segment. This information can be used to control edge display or to efficiently stitch together output from multiple clip boundaries (possibly from decomposing a non-convex clip boundary into multiple convex boundaries). 

Information about the spatial relationship between the clipped polygon or polyline and the clip region is also generated.

Autodesk.AutoCAD.Geometry.Entity2d
    Autodesk.AutoCAD.Geometry.ClipBoundary2d

Public sealed Class ClipBoundary2d
Inherits Entity2d

public sealed class ClipBoundary2d : Entity2d;