If in doubt just add layers

In a previous job I used to work as a CAD operator, a few years later when I was working in broadcast enginneering I was looking at creating some more standard Autocad templates and blocks for broadcast drawings. Ive never really got around to it, each time I do a drawing I just modify an old one from an existing template a colleague of mine made.

So ive decided to get back on it and create myself a better, more automated workflow.

One of the first things I was looking at is how to standardise layers. A few google searches later I found that the AIA (American Institute of Architects) had a system that seemed perfect (AIA CAD Layer Guidelines). With a few modifications I came up with the following….

themoog’s layering standards for broadcast Autocad drawings

As recommend by the 1997 AIA CAD layer Guidelines, layer names may be as short as six characters (discipline code + major group) or as long as sixteen characters (discipline code + major group + minor group + status). See bellow for examples.

B-VID = discipline code + major code
B-VID-SDI = discipline code + major code + minor code
B-VID-EXST = discipline code + status code
B-VID-SDI-EXST = disincline code + major code +minor code + status code

Discipline code

The discipline code is a two character field with either a hyphen or user defined modifier.

Discipline Code Discipline
A architectural
B broadcast
C civil
E electrical
I interior
M mechanical
S structural
T telecom

Major group

The major group filed is a four character field that identifies the system such as VIDEO, AUDIO etc…. Although most major groups are logically associated with specific discipline codes, it is possible to combine major group codes with any of the discipline codes. For example, B-VID, T-VID

Major Description
VID video
AUD audio
ROLL rollcall (S&W)

Minor group

This is an optional four character field for further differentiation of major groups fro example, B-VID-SDI, B-VID-CVBS

Minor Description
SDI serial digital video
CVBS composite video burst and sync
ABAL analog balanced audio
CBLN cable numbers
CABN cab numbers

Status field

The status field is an optional four character designator that differentiates new builds from remodeling and changes. For example B-VID-SDI-EXST

status description
NEWW new work
EXST existing to remain
DEMO existing to demolish
FUTR future work
TEMP temporary work
MOVE items to be moved
RELO relocated items
NICN not in contract
PHS1–9 phase numbers


annotation description
*-ANNO-DIMS dimensions
*-ANNO-KEYN keynotes
*-ANNO-LEGN legends and schedules
*-ANNO-NOTE notes
*-ANNO-NPLT non-plot info e.g. viewports
*-ANNO-REVS revisions
*-ANNO-TEXT text
*-ANNO-TTLB title blocks and sheet borders


As a general rule for all projects, drawing entities should assume the colour of the layer in which they reside. This means all colours are applied by ‘layer’ not ‘entity’

layer colour line-weight line-type
B-VID-SDI SDI Video 6-magenta continuous
B-VID-CVBS CVBS Video 3-green continuous
B-AUD-ABAL Analog balanced Audio 5-blue continuous
B-AUD-AUB Analog Unbalanced Audio 5-blue continuous

Colour Codes

code colour
1 red
2 yellow
3 green
4 cyan
5 blue
6 magenta
7 white
8 -
9 lt-grey


BTW, if anyone has any better solutions i’m still happy to hear, also I really want to know if anyone has any good cable numbering systems!