Pave
Use the Pave tool to create faces manually on an existing object.
You can also use this tool to: 
    - Blend two PolyNURBS surfaces
 - Close holes in PolyNURBS geometry
 - Convert PolyNURBS surfaces to solids
 
Pave an Optimized Shape
Pave a surface by placing points along the contour of an optimized shape.
- 
                On the PolyNURBS ribbon, select the Pave tool.

Tip: To find and open a tool, press Ctrl+F. For more information, see Find and Search for Tools. - Select points, reference points, or edges to define a rectangle. A PolyNURBS surface is automatically created
 - 
                To add another face to the PolyNURBS surface, click an open edge on the surface, and then place two more points.
                Note:
- Ctrl-click in space with the Pave tool to use the nearest global
                                plane. 

 - Ctrl-click a reference axis or plane reference to select the reference. While the reference is selected, all points you click snap to the axis or plane. Ctrl-click the reference axis or plane again to deselect it.
 
 - Ctrl-click in space with the Pave tool to use the nearest global
                                plane. 
 - Repeat the process to pave additional surfaces.
 - Right-click and mouse through the check mark to exit, or double-right-click.