| Name | Description |
| AddVertexAfter | Adds a vertex to the 2D PolyLine. |
| CreateExtensionDictionary | Creates a dictionary for the 2D PolyLine. |
| Decurve | Reverts the 2D PolyLine curve, created by IPolyLine::Fit or IPolyLine::Spline, to its original vertices. |
| DeleteCustomData | Deletes the specified custom data from the 2D PolyLine. |
| DeleteHyperLink | Deletes a hyperlink attached to the 2D PolyLine. |
| EvaluateAtDistance | Gets the point on the 2D PolyLine closest to the specified distance from the start point. Also gets the corresponding U parameter and two derivatives at that point. |
| EvaluateAtParameter | Gets the point on the 2D PolyLine corresponding to the specified U parameter and gets the two derivatives at the point. Also gets the distance of the point from the start point. |
| EvaluateAtPoint | Gets the corresponding U parameter, the distance from the start point, and the two derivatives at the specified point on the 2D PolyLine. |
| Fit | Turns the 2D PolyLine into a smooth curve consisting of Arcs joining each pair of vertices. |
| GetBoundingBox | Gets the bounding box enclosing the 2D PolyLine. |
| GetClosestPointOn | Gets the point on the 2D PolyLine that is closest to the specified point. |
| GetCustomData | Gets the specified custom data for the 2D PolyLine. |
| GetEndParams | Gets the start and end parameters of the 2D PolyLine. |
| GetExtensionDictionary | Gets the dictionary for the 2D PolyLine. |
| GetHyperLink | Gets the hyperlink attached to the 2D PolyLine. |
| GetLength | Gets the length of the 2D PolyLine. |
| GetNormal | Gets the vector normal to this 2D PolyLine. |
| GetSegmentAngle | Gets the angle at the specified vertex of this 2D PolyLine segment. |
| GetSegmentEndWidth | Gets the end width of the specified 2D PolyLine segment. |
| GetSegmentStartWidth | Gets the start width of the specified 2D PolyLine segment. |
| GetSegmentType | Gets the type of 2D PolyLine segment. |
| GetVertexCoordinate | Gets the coordinates of the specified vertex of this 2D PolyLine. |
| GetVerticesCount | Gets the number of vertices in the 2D PolyLine. |
| JoinCircleArc | Joins the specified Arc with this 2D PolyLine. |
| JoinLine | Joins the specified line with this 2D PolyLine. |
| JoinPolyLine | Joins the specified 2D PolyLine with this 2D PolyLine. |
| ReleaseExtensionDictionary | Releases and erases the dictionary for the 2D PolyLine, if the dictionary exists and is empty. |
| RemoveVertex | Removes the vertex corresponding to the specified index. |
| Select | Adds or removes the selected 2D PolyLine to or from the current selection set. |
| SetCustomData | Sets the custom data for the 2D PolyLine. |
| SetHyperLink | Attaches the specified hyperlink to the 2D PolyLine. |
| SetNormal | Sets the vector normal to this 2D PolyLine. |
| SetSegmentAngle | Sets the angle at the specified vertex of this 2D PolyLine segment. |
| SetSegmentEndWidth | Sets the end width of the specified 2D PolyLine segment. |
| SetSegmentStartWidth | Sets the start width of the specified 2D PolyLine segment. |
| SetVertexCoordinate | Sets the coordinates of the specified vertex of this 2D PolyLine. |
| Spline | Turns the 2D PolyLine into a curve using the vertices as control points. |
| Split | Splits the 2D PolyLine at the specified vertex and creates a new 2D PolyLine. |
| Straighten | Straightens the 2D PolyLine between the two specified vertices. |