This revised manual represents the latest effort of the Tri-Service Technical Center (TSTC) to standardize CADD requirements for A/E/C design and construction documents. The primary goal of the manual is to develop a CADD standard that is generic enough to operate under various software (such as MicroStation and AutoCAD) and incorporate existing industry standards when possible. Are you aware that many of the Civil Engineering standards we use today where first published for the Engineering classes at West Point in 1830? Therefore it is not much of a stretch for us to assume that the DoD will, by default, set CADD standards as well. The Global Positioning System and the Geographic Information Systems we use today were financed primarily to preserve US national security during the Cold War.

The following comments apply only to the 4/01/98 downloaded review copy of the standards which will be revised in the final draft. We note here that the Chapter 2, Table 3, Standard Line Styles has typographical errors in our PDF printout.

The TSTC A/E/C CADD Joint Committee provides for the ISO international metric drafting standards, coming soon to your neighborhood by Federal decree. For as of January 1, 1992, in accordance with Public Laws 94-168 and 100-418, and Executive Order 12770, all new and revised construction standards and criteria must be developed using this SI metric standard.

Many good citizens believe that many of the SI standards should have no place in our day-to-day lives because they will surely not be cost effective to implement, and their use will not add any intrinsic value to Construction Site Planning or Building Design working drawings. This is truly an International non-problem for the same drawing, if need be, can be dimensioned and plotted to any scale required with most programs. Try to imagine how well your typical Land Title Company clerk will convert the existing recorded property description distances from poles, rods, or feet to meters and the deeded bearings to the metric 400 grad replacement for the 360 degree compass. Massive quantities of ‘GIGO’ await the American Home Owners and Business Organizations of the future.

The two most basic concepts in the TSTC standards that allow DGN and DWG files to work cross platform are:
1.) The Standards intentionally omit the use of polylines because they do not readily translate between other CADD systems and are unique to the AutoCAD file format.
2.) MicroStation users must in turn use a standard line color rather than line weight for indicating plotted line width.

An essential step forward was the standardization of which screen color is equal to what pen size. But we seem to be stuck in the past here as some CAD programmers just can’t seem to realize that with the modern Raster plotter/printers we now sometimes need to use color as color. Even VersaCAD had a pen number entity property way back when.

The standard ISO line types shown below are not included in all available programs but in most the user can easily add them as required. AutoCAD R-14 takes the usual Autodesk closed system approach and includes the ISO line types but with their own proprietary line type names.

A comparison list of the ISO-128 Metric line types:

The TSTC standards limit the number of different fonts that may be used in order to facilitate file conversion from one Design Drafting program to another. This is a very good and much needed practice. I can’t count the number of AutoCAD and DXF files we have received in this office containing strange third party fonts. So for the sanity of all Design Drafting program operators please adhere to the standard. AutoCAD R-14 and LT-97 reach new highs of incompatibility by including TrueType versions of their standard SHX font files while including the PostScript fonts provided with earlier releases. My advise here is to convert to the vector based .SHX fonts while saving to AutoCAD drawings and only use the R-12 DWG and DXF file formats. Perhaps when Unicode and OpenType become the future PC standard, replacing both the PostScript and TrueType faces, we will then get proper and full character set A/E/C technical font faces.

The Standard Vector Sans Serif Font Conversions Required: