Using Layers to Organize Your Drawing - AutoCAD 2011 and AutoCAD LT 2011: No Experience Required - page 241

CHAPtER 6
using Layers to
organize Your Drawing
Before the age of computers, drafters used sets of transparent overlays on
their drafting tables. They were sheets that stacked one on top of the other, and
the drafters could see through several at a time. Specific kinds of information
were drawn on each overlay. All of them related spatially so that several over-
lays might be drawn for the same floor plan. Drawings for each discipline, such
as plumbing, electrical, or HVAC, as well as charts and tables, were drawn on
separate overlays so that the floor plans did not have to be replicated for every
type of drawing produced. Each overlay had small holes punched near the cor-
ners so the drafter could position the overlay onto buttons, called registration
points , that were taped to the drawing board. Because all overlays had holes
punched at the same locations with respect to the drawing, information on the
set of overlays was kept in alignment.
To help you organize your drawing, AutoCAD provides you with an amaz-
ing tool called layers , which can be thought of as a computerized form of
the transparent overlays, only much more powerful and flexible. In manual
drafting, you could use only four or five overlays at a time before the infor-
mation on the bottom overlay became unreadable. (Copying the drawing
meant sending all the layers through the blueprint machine together.) In
AutoCAD, you aren't limited in the number of layers you can use. You can
have hundreds of layers, and complex CAD drawings often do.
Creating new layers
assigning a color and a linetype to layers
Moving existing objects onto a new layer
Controlling the visibility of layers
Working with linetypes
Isolating objects by layer
Using the action recorder
Creating layer states