Overview of Two-Dimensional and Three-Dimensional Polylines

A two-dimensional polyline is a parametric entity that specifies a set of two-dimensional vertices and a set of linear or arc segments connected in a single curve in a plane. A two-dimensional vertex is an individual entity that specifies a position, type, and geometrical parameters.

A three-dimensional polyline is a parametric entity that specifies a set of three-dimensional vertices and a set of linear segments connected in a single curve in world space. This entity stores three-dimensional vertices, which are the individual entities that specify a position, type, and some geometrical parameters.

Structurally, the two-dimensional and three-dimensional polyline objects are containers of vertices. Each vertex is an individual entity in the database. An owner of a vertex is the polyline in which it is appended.

For a two-dimensional polyline:

For a three-dimensional polyline:

The two-dimensional and the three-dimensional vertex objects are represented by the OdDb2dVertex and OdDb3dPolylineVertex classes, which allow users to access a two-dimensional and three-dimensional vertex entity and manipulate its properties. The OdDb2dVertexPtr class and the OdDb3dPolylineVertexPtr class are the typified smart pointers to an instances of those entities and are used for storing and passing references to the vertex objects.

For working with polylines use the OdDb2dPolyline and OdDb3dPolyline classes, which represent two-dimensional and three-dimensional polylines and allow users to access polylines and manipulate their properties. The OdDb2dPolylinePtr class and the OdDb3dPolylinePtr class are the typified smart pointers to an instances of those entities and are used for storing and passing references to the polyline objects.

There is one more class, named OdDbPolyline. It is similar to the OdDb2dPolyline class but uses a more compact vertex storage; all coordinates are stored inside the OdDbPolyline entity and not as separate entities. Also, it can't be curve or spline fitted.

To create and initialize a new instance of polylines, see Overview of Specific Entities.

See Also