Layer Purpose Definitions
- Last UpdatedAug 13, 2025
- 2 minute read
Sets the layer defaults and attributes available to the user.

The scrollable list displays all currently defined layer defaults. The highlighted layer is updated by any new settings entered.
All layers have a PURP attribute which is set to a four character keyword which identifies the purpose for which that layer is intended to be used. Layer purposes cannot be duplicated under any one owning View. The Layer Purpose box on the window allows you to specify the purpose as a three-character string (the fourth character is added automatically when setting PURP so that multiple layers of a given type can be created under a single View).
For example, if the administrator has defined a layer with its purpose defined as DIM and a user decides to have three dimension layers in each View for, say, steelwork (STLDIM), equipment (EQUDIM) and piping (PIPDIM), then the View contents might be, for example:
|
Element Type |
Name |
PURP |
|---|---|---|
|
VIEW |
XYZ0001/S1/V1 |
n/a |
|
LAYE |
XYZ0001/S1/V1/STLDIM |
DIMA |
|
LAYE |
XYZ0001/S1/V1/EQUDIM |
DIMB |
|
LAYE |
XYZ0001/S1/V1/PIPDIM |
DIMC |
where the fourth character of the PURP (A, B or C) distinguishes the individual DIM layers.
Note:
The purpose keyword TAG is reserved for autotagging layers. It is a requirement of
the application and must always be defined in the layer defaults. If it is omitted,
a TAG layer purpose definition is appended automatically during default initialization.
The TAG layer purpose definition cannot be deleted.
The Setup File box is used to specify the macro file that is executed to set the layer attributes after a layer has been created. Default macro files are supplied with the product. For example, DRA-GEN-DEFLAY defines the default attribute values for layers which allows users to create layer annotations to a common standard.
You can copy and modify these macro files to meet company and/or project standards. You can also create new files for other purpose types of your own definition.
The Attribute Group check boxes, Dim, Note, Text, Lab and Symb allow you to specify which attribute types display on the Layer Attributes window. The combination which applies to each of the currently defined layers is indicated by the + (selected) and - (unselected) codes in the scrollable list. To change these, turn the attributes on and off as required.
To delete the currently selected layer default, click Delete.
To associate a layer default with a setup file, click Insert.
Click OK to set the layer defaults or Cancel to discard any changes and close the Layer Purpose Definitions window.