2011

NOTE The number of layers that you can create in a drawing and the number of
objects that you can create on each layer are practically unlimited.
Choose Layer Names Carefully
A layer name can include up to 255 characters (double-byte or alphanumeric):
letters, numbers, spaces, and several special characters. Layer names cannot
include the following characters:
< > / \ “ : ; ? * | = ‘
In many cases, the layer names you choose are dictated by corporate, industry,
or client standards.
The Layers palette sorts layers alphabetically by name. If you organize your
own layer scheme, choose layer names carefully. Use common prefixes to
name layers with related drawing components, this makes it easier to locate
and manipulate groups of layers at a time.
NOTE If you consistently use a specific layering scheme, you can set up a drawing
template with layers, linetypes, and colors already assigned. For more information
about creating templates, see Use a Drawing Template File on page 58.
Select a Layer to Draw On
As you draw, newly created objects are placed on the current layer. The current
layer may be the default layer (0) or a layer you create and name yourself. You
switch from one layer to another by making a different layer current; any
subsequent objects you create are associated with the new current layer and
use its color, linetype, and other properties. You cannot make a layer the
current layer if it is frozen or if it is an xref-dependent layer.
Remove Layers
You can remove unused layers from your drawing with PURGE or by deleting
the layer from the Layers palette. You can delete only unreferenced layers.
Referenced layers include layers 0 and DEFPOINTS, layers containing objects
(including objects in block definitions), the current layer, and xref-dependent
layers.
WARNING Be careful about deleting layers if you are working on a drawing in a
shared project or one based on a set of layering standards.
170 | Chapter 15 Control the Properties of Objects