Layers are used to separate elements logically. Each tool has a default layer assignment: when you place an element using that tool, the new element is automatically placed on the corresponding layer.
An element can only belong to a single layer.
Note: Doors, Windows, Openings, Wall Ends and Corner Windows do not have separate layers; they are handled together with the layers of the wall into which they are placed. Cameras do not have layers.
Each Archicad project has a single layer set, managed in Layer Settings. However, the Layout book can have different settings than those used in Model views.
The Archicad Layer is a special layer that cannot be deleted, hidden or locked, since an Archicad project must always contain at least one layer. In case of a file error, any elements that may have lost their layer definitions will be placed on the Archicad Layer.
Use layers to prevent intersections
Use separate layer settings for the Layout Book
Place all elements on a single “active layer” (Simulate AutoCAD work methods)
For general information: see Using the attribute dialogs.