Layers
You can create layers in a SolidWorks drawing document. You
assign visibility, line color, line thickness, and line style for new
entities (annotations and assembly components) created on each layer.
New entities are automatically added to the active layer.
Use
layers also with dimensions, area hatch, detail circles, and section lines.
Components, in either part or
assembly drawings, can be moved onto layers. The Component Line Font
dialog box includes a list for selecting a named layer for the component.
If you import a .dxf
or .dwg file into a SolidWorks
drawing, layers are created automatically. The layer information (names,
properties, and entity locations) is retained.
If you export a drawing with
layers as a .dxf or .dwg
file, the layer information is included in the file. When you open
the file in the target system, the entities are on the same layers and
have the same properties unless you use mapping
to redirect the entities to new layers.
You can assign document-level layers
to each type of dimension, annotation, table, and view label detail.
To create a drawing layer:
Click Layer
Properties 
(Layer or Line Format toolbar).
In the dialog box, click New, and enter the Name
of a new layer.
NOTE:
If you save the drawing as a .dxf
or .dwg file, the layer name may
be changed in the .dxf or .dwg file as follows:
Specify the line format for entities
on that layer as follows:
To add a description, double-click
in the Description column and
type text.
To specify the line color, click
the Color box, select a color,
and click OK.
To specify the line style or
thickness, click in the Style
or Thickness column, and select
the desired style or thickness from the list.
Repeat steps 2 and 3 to create
as many layers as necessary.
Active. An arrow 
indicates which layer is active. To activate a layer, click
beside the layer name. The active layer is also displayed on the Layer
toolbar.
On/Off. A yellow lightbulb 
appears with any layer that is visible. To hide a layer,
click its lightbulb. The lightbulb turns white 
, and all
the entities on the layer are hidden. To turn the layer back on, click
the lightbulb again.
Move. To move entities to another
layer, select the entities in the drawing, select the layer to move to,
and click Move. Alternatively,
you can select the entities, and in the Layer toolbar, select the layer
name.
Delete. Removes a layer.