Every object in AutoCAD belongs to a layer. A layer can be made invisible, causing the objects assigned to that layer to disappear from view (this is called turning a layer off). A layer can be locked, protecting the objects assigned to that layer from accidental erasure or displacement. A layer can be defined as non-printing, so that its objects are visible on screen but do not print.
TO CREATE A NEW LAYER:
Type LAYER. In the resulting Layer Properties Manager dialog box, use the New button to create and name a layer; use the Current button to choose a layer for drawing (newly drawn objects appear on the current layer); use the color swatches to assign colors to layers.
TO DELETE A LAYER:
In the Layer Properties Manager dialog box, highlight a layer name and click Delete. If the layer contains objects, it cannot be deleted. Typing PURGE at the command prompt will omit unused layers.
TO CHANGE AN OBJECT’S LAYER:
Use any one of these methods:
Type CHANGE (or –CH). When prompted, select the object(s) and click enter. Type P for Properties; LA for Layer; and then the name of the layer to which you wish to assign the object(s).
OR use the layer pulldown menu in the Object Properties toolbar. Click the object(s); then click the pulldown menu and release the mouse over the layer to which you wish to assign the object(s). Click the escape key to deselect the object(s).
OR click ctrl-1 to display the Properties palette. Click on an object, or a group of objects. Click next to the word “Layer” in the Properties palette and select a layer from the pulldown menu. Click the escape key to deselect the object(s).
OR use the MA (“match properties”) command to assign the properties of a source object, including its layer assignment, to one or more other objects.