A layer key override enables you to change the default layer names specified by one or more layer keys. The structure of layer names is determined by the descriptive fields in the layer standard definition. You can allow overrides on all the layer keys within a layer key style, or you can select individual layer keys that you want to override. You can override all descriptive fields that make up the layer name, or you can specify which descriptive fields to override. You can apply overrides to any layer keys in a layer key style that is based on a layer standard.
For example, in the AIA 2nd Edition layer standard definition, the Discipline Designator field assigns a description and the Major field assigns a name by default. By using layer key overrides, you can change the values specified in these fields and add values in the unused fields, Minor Code and Status.
The information that you enter to create layer key overrides must conform to the field width and value types specified by the layer standard definition. For example, you cannot specify a four-letter override in the Discipline Designator field in the AIA 2nd Edition Layer Standard, because the maximum width for the Discipline Designator field as specified in the AIA layer standard definition is 1. To modify the descriptive fields, you must edit the layer standard definition.
After you add overrides to a layer key style, you can turn the overrides on and off in your current drawing. When the layer key overrides are on, objects that you create are placed on layers defined by the layer standard definitions and overridden with the values that you specify. When the layer key overrides are off, objects that you create are placed on the layers defined only by the layer keys. You can start using the layer key overrides immediately after you specify them, or you can use the Overrides On/Off command to switch them on later.
Layer key overrides do not change the layer assignments of existing objects. Only objects added after an override is enabled are affected by the override.