Written with the use of AutoCAD in mind, however principles apply to other CAD packages.
Core concepts
All layer names are prefix with a predefined set of numbers is the core of the concept behind this system. The first digit represents the discipline and the following digits refer to the object type (doors, columns etc.).
Benefits
Multiple drafters can work together on the same projects because the layer list is ordered and structured.
In theory elements from different disciplines can be drawn in a single file – In practice XREF-ing to individual files may be easier to manage.
The preset numbering of the layers allows for CAD programs to filter and manipulate the drawing easier. A program can search for those set parameters.
Execution
The layer naming can be just the numbers or with the following extensions:
- X = eXisting: the objects drawn are existing conditions
- D = Demolition: the objects drawn have to be demolished
- N = Non-structural: both Architectural and Structural may require the use of this, for example, defining the structural and non-structural walls.
- P = Proposed: Generally drawings are for proposed works anyway, however there may occur cases where it may be necessary to make the distinction.
- –description = the dash and description can be used on all layers; example 105-room names, 105X-room names.
Combinded Disciplines – sample list
| Layer No. | Description | Layer No. | Description |
| 000 | Hatch boundary | 410 | Hardware |
| 001 | All general linework | 420 | Paving |
| 021 | Title sheet | 439 | Access Floors |
| 030 | Dimensions | 440 | Base layer for Xrefs |
| 032 | Room names | 444 | Partitions |
| 033 | Room numbers | 450 | Roofing |
| 034 | Floor finishes | 459 | Suspended ceilings |
| 035 | Detail reference no. | 460 | Curtain walls |
| 036 | Section reference no. | 461 | Windows |
| 037 | General Arch Text | 465 | Doors |
| 038 | General Struct Text | 510 | Cladding |
| 039 | Amendments/Revisions | 552 | Tiling |
| 040 | Grids | 553 | Resilient Finishes |
| 050 | Levels | 560 | Plastering |
| 051 | Contours | 570 | Painting |
| 060 | Symbols | 580 | Graphics, Artwork |
| 062 | Hatch Patterns | 591 | Carpets |
| 072 | Site Features (kerbs, manholes etc.) | 610 | Loose Furniture |
| 140 | Vegetation (Trees etc. | 611 | Furniture |
| 210 | Groundworks | 615 | Furniture Text |
| 215 | Piling | 722 | Stormwater |
| 220 | Concrete | 730 | Sanitary Services |
| 230 | Masonry Walls | 737 | Plumbing Fixtures |
| 235 | Stonework | 740 | Water Services |
| 250 | Structural Steel | 783 | Fire Protection-Sprinklers |
| 260 | Metalwork | 884 | Fans (ceiling and exhaust etc.) |
| 270 | Woodwork | 922 | Roadworks |
| 280 | Glazing | 700 | Hydraulics |
| 709 | General Hydraulic Text | 725 | Toxic Wastes |
| 720 | Drainage | 727 | Sewer Treatment |
| 728 | Special Services | 740 | Water Services |
| 741 | External services – mains | 742 | Cold Water Supply |
| 743 | Hot Water Supply | 745 | Chilled Water |
| 747 | Irrigation | 880 | Air Handling Ductwork |
| 749 | Condensaed Water System | 887 | Exhaust Systems |
| 780 | Fire Protection | 828 | Lights |
| 787 | Fire and Smoke Detection | 892 | Lifts |
| 791 | Voice and Data | 892 | Lifts |
| 800 | General Electrical | 846 | Security Systems |