Spring Semester [ 2001-2 ]
Section 21 - Linda A.E.Cripps 
content update: 12 February 2001

 The National CAD Standard
Layer Naming Conventions

Layer Name Convention Information

History of Standard Layer Names
Short Summary of AIA CAD Layer Guidelines
Short Summary of Course Layer Guidelines
Notes on Colors and Layers
Course Layer Guideline References 


History of Standard Layer Names  [top]

The AIA CAD Layer Guidelines have been incorporated as part of the National CAD Standard. The development of a standardized CAD layer system pre-dated the work of the CSI's Uniform Drawing System. Rather than reduplicate the wheel, so to speak, the committee on the UDS and the National CAD standard decided to use the CAD Layer Guidelines under development by the AIA.

In terms of implementation of the National CAD Standard, many offices elect to continue with their prior layering systems, rather than adopt the AIA CAD Layer Guidelines. Therefore, it is highly likely that an architectural technician will be using an "office standard" for layering CAD drawings, but it may not be the AIA standard. As the curriculum development for AET 241 began prior to the finalization of either the AIA Layer guidelines or the National CAD standard, a decision had to be made several years ago concerning a layering system. A course standard layer system was developed that uses a logic similar to the AIA system, but is not identical to it. In considering updating all of the course CAD files to a different layering system, I encountered a similar dilemma as most offices face at the moment.

The course will continue to use the "course standard layer system", rather than implement the AIA system. This is because:

Short Summary of AIA CAD Layer Guidelines  [top]

The student should refer to the Jefferis textbook in Chapter 3 - Applying AutoCAD Tools to Commercial Drawings for an more extensive discussion of AIA Standardized Layer Names.  There is also an online lecture on the AIA Standardized Layer names.

Like the UDS file naming system, the AIA layer guidelines were developed to provide a standardized system that could be adapted to small and large projects, and has some built in flexibility. Therefore, it has both "short format" and "long format" names, and in addition to pre-defined elements, it allows for the addition of "user-defined" modifiers, to customize the basic system to particular office or project needs.

The standard format for AIA long format layer names is:

where "DD" represents the major group identification which corresponds to the drawing disciplines - "A" for Architectural, "C" for Civil, "E" for Electrical, etc.  The AIA system allows for the use of one or two characters for the discipline designators, depending upon specific office needs.  The next four characters "MJGP" are defined as the "major groups" within the discipline identifcation. Some AIA major groups are "FNDN" , "WALL", "SLAB", etc. The next four characters "MJGP" are termed the "minor groups" to further subdivide the major groups.
The layer name need not contain the last four characters, "USDF", as this is the user-defined modifier and is added at the user's discretion.
For example:
C-WALL-CMU would be the layer for the concrete masonry units in the exterior walls on structural drawings.
A-WALL--CMU would be the layer for the concrete masonry units in the exterior walls on the architectural drawings, while 
A-WALL-GYBD would be the layer for the gypsum board construction in the exterior walls on the architectural drawings, and
AI-WALL-GYPD-REN would be the layer for gypsum board renovation in the exterior walls of architectural interiors drawings

Short Summary of Course Layer Guidelines  [top]

The course layer guide lines follow a similar structure as the AIA short format names.
The course standard format is:

"D" is the category for discipline, in this course this will always be "A". What differs slightly from the AIA system, are the specific definitions fo the major groups and minor groups, "MJGP" and "MNGP" categories.  As the AIA standard has evolved and the oppotunity for revision of the class standard has occurred, these differences are becoming fewer and fewer.

The minor group names and modifiers for the course layer system are based on the construction components and loosely modeled on the CSI 16 Division Masterformat categories - SHFT - shaft wall, STFM - structural frame, STAR - stair, DOOR - door, SPEC - specialites, etc.

The course will make use of the "USDF", user-defined layer category only on the tenant plan drawings.

Some examples as above would be:
A-DOOR-UNIT would be the layer for the drawing elements of a door unit, while
A-DOOR-IDEN would be the layer for the door mark symbol., A-GRID-DIM would be the layer for the dimensions of the structural grid, while
A-ANNO-DIM would be the layer for the other dimensions of the drawing
At the end of this reference page, there are links to the documentation that exists for the course layer guidelines.

Notes on Colors and Layers [top]

Prior to AutoCAD 2000, the color definitions for the layers were significant as they directly correlated to the plotter formatting for determining the lineweights on the drawing. In the current version of AutoCAD, the lineweight can now be defined as a drawing entity property, and so the strict adherence to the standard layer colors is not required to produce a correctly plotted drawing. It is recommended that the standard layer colors in the prototype drawings be used. They are best seen on a white display background, rather than a black one. ( This can be modified in the "Tools - Preferences - Display" menus )

Course Layer Guideline References [top]

Three different documents on the course layer guidelines are available, both by downlink from this web page, or from the Asylum H:\aet241_cripps network drive.
Layer Naming Conventions - Explanation of the course layer name system
Download file Word 2000 format

Layer Naming - Reference for Complete Layer Names
Download file Word 2000 format

[cadlyltn_022.doc] NOTE: This document is UNAVAILABLE for Spring 2002 term.it is under revision to consider integration of v2 of National CAD Standard.
Layer Naming - References for Drawing Types
Download File Word 2000 format - Detail Drawings

Download File Word 2000 format - Plan Drawings

Download File Word 2000 format - Elevation Drawings


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