Within the Object Property Settings dialog box, you can specify what layer the object must be created on.
When Automatic Property Management is enabled, AutoCAD Mechanical toolset commands honor this setting and always create objects on the pre-assigned layer. If the layer does not exist, AutoCAD Mechanical toolset commands create the layer on the fly. Layers that are created by AutoCAD Mechanical toolset commands in this manner are referred to as mechanical layers.
Because mechanical layers are created on the fly, AutoCAD Mechanical toolset provides the ability to pre-define mechanical layers and their properties with the help of an entity that is referred to as a layer definition. Similar to how a block definition is used by AutoCAD commands to create instances of blocks, AutoCAD Mechanical toolset commands use the layer definition to create layers on the fly. All mechanical layers have a corresponding definition.
You use the AMLAYER command to specify properties for layer definitions, similar to how you use the LAYER command to specify properties for layers.
AutoCAD Mechanical toolset ships with several predefined mechanical layers. Some layers are shared among several objects while other layers are exclusive to particular objects. The default layer assignments have been tried and tested for optimum use over several releases of AutoCAD Mechanical toolset. However, you may need to change these assignments to satisfy company standards or customer requirements.
There are two ways by which you can customize layer assignments. You can rename the existing layers to reflect the company standards or create your own set of mechanical layers and assign them to objects. However, when assigning your layers, we advice you to exert caution when sharing layers with different objects.
For example, if you share a single layer with construction lines and hatches, every time you turn off construction lines, the hatches also hide. In order to avoid such issues, we recommend that you do not share layers among objects. If you have a compelling reason to share layers, use the default layer assignment as a guideline for objects that must go together.
The layers that standard parts and features are created on, by default, depend on the context that they are inserted in the drawing. AutoCAD Mechanical toolset uses a complex algorithm to select the layer. However, you can stop AutoCAD Mechanical toolset from selecting standard parts automatically and specify that they be created on a preassigned mechanical layer(s). Alternatively, you can specify that AutoCAD Mechanical toolset should create standard parts on the current layer. If so, AutoCAD Mechanical toolset commands always creates standard parts and features on the current layer. The responsibility of changing to the appropriate layer then becomes yours. Consequently, commands that depend on objects being drawn on specific layers may not work as expected. We recommend that you leave this setting at its default value; Auto.