Creating Solids and Surfaces from 2D - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 91

Creating solids and surfaces by

extrusion

Often we create a 3D model from 2D drawings by extruding (giving height) to planar
entities or closed areas. For instance, in architecture, we may construct walls from
plan views. The following sections present the commands for extrusion.

Extruding 2D objects

Probably the most used command for modeling in 3D is EXTRUDE , which is presented
next.

The EXTRUDE command

The EXTRUDE command (alias EXT ) allows for extruding or giving height to planar en-
tities, thus creating volumes. The command starts by showing information about the
wire frame density and the MOde default option; it then asks for the objects to be ex-
truded:

Command: EXTRUDE
Current wire frame density: ISOLINES=4, Closed
profiles creation mode = Solid
Select objects to extrude or [MOde]: Selection

By default, the command prompts the height of extrusion:

Specify height of extrusion or [Direction/Path/
Taper angle/Expression]: Value

All the selected objects are extruded. If the original object is closed, a solid is created,
else a surface is created. By default, when creating a solid, the original object is
erased. This behavior is controlled by the DELOBJ variable.