A Layer naming standard is the cornerstone of any CAD system and is at the heart of efficient drawing production. So now let’s see how to use layernames to manage drawing data.
Benefits of a layer naming Standard:
- No time wasted thinking what to call a new layer definition.
- No time wasted working out the function of an existing layer.
- No confusion over the order of or abbreviation of layer name fields.
- Drafters are interchangeable without confusion.
- Drawings are shareable without confusion.
- Layers with common characteristics can be managed using wild-cards.
- Editing time is reduced.
- Accuracy is improved.
Much effort has been put into a producing a Layer naming Standard. In Europe the outcome was ISO/DIS 13567, a generic system applicable to all professions. The result was somewhat complex as it tried to be all things to all people. Nevertheless the principles are very sound and will provide a basis for your own custom system. The US developed its own system based somewhat on ISO/DIS 13567. Neither of the two, or any other system that I know of, has provided a consistently workable standard capable of practical adoption.
Nevertheless systematic layer naming is the key to good data management. Any system is better than none but Layer naming continues to be one of the most tedious and time-consuming, yet most important, tasks in CAD.
Layer properties
MycadLAYERS, like many other layer naming standards, adds to the properties of objects by embodying properties in the LAYERNAME itself. Such properties could be Object-type, Job-status, Drawing-type, View-point and Location of the objects in a drawing set. For example: “BRI 3 7 X 511 P 02” (expanded for readability) that means: “BRIck color3(green) line-type dashed(7) Xisting Plan-view level 02”. This defines the building element’s drawn graphics, its project status, drawing type and location in a drawing set. Looking a little closer it can be seen that the first five characters define drawn nature of the object and the last seven where they belong in a drawing set. If a drawing has a simple single purpose there is no need to include the latter seven characters. A five character layer name may be sufficient and in fact for many simple drawings any more is a waste of time. So much for complex national layer-naming standards. MycadLAYERS provides an automated system for generating and managing layernames and their properties and permits the use of either five or twelve character layernames or may simply be turned OFF when not needed.
MycadLAYERS makes the following AutoCAD commands virtually redundant:
- LMAN
- VPLAYER Newfrz and Vpvisdflt options
- LAYERPALETTE
- LAYERSTATE
Layer name length
MycadLAYERS provides for two different layer name lengths of either five or twelve characters, or may be turned OFF, depending upon the drawing requirements; twelve for drawings with defined Workzones and five for simple one-level one-concept drawings or OFF if a naming standard is not required.
When MycadLAYERS control is set to 5 or 12 characters new layer names created by MycadLAYERS commands adopt the correct length and format according to the current setting of layer-name length. When layer control is OFF, uncontrolled entry of layer names is permitted. A one-off uncontrolled entry may also be achieved without re-setting the current-layer-name length by pressing ` (back quote) prior to entering the layer name. This has the effect of turning layer-name length to OFF for the current entry only. (similar to invoking a generic Autocad command using a MycadKEYS alias).
By default MycadLAYERS starts up with layername control OFF. The user toggles between: OFF, 5chr, or 12chr by entering the alias $7<enter> repeatedly until the required number of layers is set. You may wish to encode your Function Key 7 to acheive the same.
Saving MycadLAYERS layer settings
Layername length and associated WORKZONE settings are saved with the drawing from session to session and may be easily changed at any time. The results are displayed in AutoCAD’s status line.
A brief note about Renaming layers:
AutoCAD provides a means of renaming layers summarising the process as:
- The layer definition receives a new name.
- All objects referencing that layer automatically update their Layer property.
- The visual appearance does not change unless the new layer definition differs.
BUT this only works if the layer naming strategy permits it and the layer properties implied by the new name match the visual properties of the old layer name. An inherent flaw in the MycadLAYERS naming system is that the appearance of the objects is encoded in the layer name so that using AutoCAD the new layer name must retain the color and line-type attributes of the original layer name wheras MycadLAYERS automatically adjusts appearance to the new name.
Changing an object’s layer name
A layer is an environmental condition with a list of property settings (with or without objects) not a LOCATION from or to which objects may be moved. Objects are not moved into layers. Their Layer property is changed to reference a different layer definition. Renaming a layer effectively creates a NEW layer with a new name albeit it may have the same properties as the former. The LAYER definitions remain in the system whether or not there are any objects that reference them. Changing appearance properties of an object from BYLAYER to a specific value does not change the LAYER’s application to other objects with the same LAYER-NAME. Unreferenced layers may be purged.
Author’s note:
There is no clear evidence as to when AutoCAD first introduced a layer rename facility but when MycadLAYERS was developed there was no purpose in renaming layers. MycadLAYERS makes layer control so easy and precise that re-naming layers or moving objects between layers was not contemplated.