Creating Solids and Surfaces from 2D - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 92

If the object is closed but we want to create a surface, we must change the MOde
option to Surface before proceeding to the selection.
Other command options are as follows:
• Direction : This option creates an inclined extrusion. It prompts for two
points that specify length and angle:
• Path : This option creates an extrusion along a path. It prompts for the se-
lection of a linear object.