In AutoCAD, layers are used for organizing a drawing. Objects can be assigned to layers and you can e.g. hide entire layers when you do not need to see them. You can also enfore colors and linetypes for entire layers, as well as other property standards. All in all, this makes it more easy to work with complex drawings.
A basic layering principle in AutoCAD is to define a layer for a specific function of purpose and to assign objects to the layer matching that purpose of function. Another approach would be to define layers by location.
In AutoCAD, the LAYER command will open the Layer Properties Manager. Here you can see all layers in your drawing. You can disable layers here and you can see which layer is currently active.
In the Layer Properties Manager one can click the light bulb symbols to hide or show layers. One can also add or remove layers here. Adjustment of layer colors is also possible here. Clicking the “sun” symbol will freeze the layer. Freezing layers is similar to disabling them. According to Autodesk, freezing layers instead of simply disabling them has some performance advantage . Lastly, in addition to coloring and lintypes also the transparency is a standard layer property which can be maintained in the Layer Properties Manager.
In below example I added 2 more layers, and I renamed them. Currently the color is set to white for all layers.
Below are the objects in the drawing. The objects are assigned to different layers.
I now adjust the color settings in the Layer Properties Manager. Below you see the colors chosen.
This will change the colors of the objects in the drawing, depending on which layer they have been assigned to.
There are some general rules in AutoCAD:
Rule 1: Layer 0 exists per default. Its name cannot be changed. In general, you should not use this layer for adding objects but instead create a new layer which you can rename as you deem reasonable.
Rule 2: Defpoints is a layer that exists per default in any drawing that contains at least one dimension object.
Rule 3: Everything that you might add to the drawing but that you would lateron not want to print should be added to some sort of “background-layer”.
Rule 4: All hatches and fills should be assigned to a hatch & fill layer, since in this way you can easily turn fills on and off.
When working inside the drawing your can change the current layer via the LAYER command or by clicking the drop-down menu in the AutoCAD home tab.