When you create a model documentation drawing view, the program draws view geometry on pre determined layers, depending on what the geometry represents.
For example, a groove on the front side of a part is drawn on a layer named “visible” in the front view. The same groove is drawn on a layer named “hidden” in the back view, because it represents an invisible edge.
Layers are created on demand as and when drawing views are created. Furthermore, only the layers required to support the geometry in a view are created. For example, a view of a model space solid with the Hidden option set to visible lines creates only the MD_Visible layer. For the same view, changing edge visibility to display tangent edges results in creation of the MD_Visible Narrow layer.
Once a layer is created, it is not deleted automatically, even if the layer is no longer used. You must explicitly delete or purge unreferenced layers.
The default line type patterns and line weights are based on ISO 128-20:1996. You can however use the layer manager to change these parameters.
If your company conventions require you to stick to specific layer names, you can rename the layers, after they are created. Subsequent views that you create use the renamed layers.