Tech Biz Writing

DDS is a documentation/methodology employed in system design. It can be used for both electrical and mechanical engineering disciplines, covering hardware, software, logic and functional dimensions. It has become a versatile tool for designers of any system, allowing detailed recording of progress as the project develops. It’s not a publications application, but more a methodology and information system for development purposes. Writers, however, may be involved in its implementation, and will refer to it during the writing of other project documentation. It is a good example of documentation and information organization systems, which is how we are using in here.

The Development Documentation System was begun in the Sixties by the Naval Applied Science Laboratory in America. Since then much work has been done on it in the UK, and it has been used effectively for some naval and military projects. A full account of the procedure can be found in the MoD’s Naval Weapons Specifications.

DDS uses a hierarchical approach to the recording of design information. The levels move from the general to the detailed: from the highest and broadest level (showing the system itself) through as many intermediate levels as are considered necessary, to the lowest (illustrating the smallest detail). The format used will depend on the engineering discipline involved, and whether the subject matter is software, hardware, function or logic orientated. Advantages of DDS include:

* Ease of update.
* Results of studies or analysis may be incorporated.
* Evolves with the project, allowing a dynamic approach to documentation.
* Provides a complete record of the design stages.
* Enables a testing philosophy to be formulated at an early phase of development.
* Allows a wide choice of record formats.
* Co-ordinates all design information without necessarily replacing standard publications’ procedures.
* Presents maximum information in minimum time.
* Excellent for monitoring progress.
* Encourages a systems approach to design which smoothes over any interface
problems.

DDS is an example of a systems approach to technical documentation which authors may not come across often unless working on military projects. Newer technology methods have developed and extended it to match the complexity of modern engineering design. But if a technical writer gets involved in a very large project, such as the development of an aircraft, he/she will be plunged into a documentation implementation arrangement very similar to DDS.

Next: 46. Diagnostic and Maintenance Documentation

Perspective is an artist’s attempt to come to terms with the world as it exists. To represent objects in space as they really are — or seem to be — on a flat plane (paper or screen), various expedients have to be employed. The essence of it is to project the three-dimensional object onto the two-dimensional surface in such a way that the apparent linear relationships of receding planes are maintained, or, in some cases, exaggerated. There are three types of linear perspective:

* One-point (parallel)
* Two-point (angular)
* Three-point (oblique)

For a cube the first would show one face only; the second would show two; and the third, three faces. Distortions would appear if a one-point drawing showed two faces; two-point showed three faces, and so on. Only three-point perspective allows a true depiction of three faces of an object. For this reason it’s usually used in technical illustration.

Photographs may also be used for line drawings as a guide for the illustrator. This is not as simple as it sounds since there are many problems associated with camera angle and obtaining the right axis or axes through the equipment. Photographic prints may be useful as a simple introductory guide for exploded views or cut-aways.

A further technique is to draw in the outlines and relevant details on a photographic plate with ink, and to bleach out the image with potassium ferricyanide leaving the line drawing intact. This is not frequently used in technical work nowadays, but it can be cheap and effective in certain circumstances.

Next: 39. Half-Tones

Diagrams proliferate in the work of a technical writer. They are probably the most common form of information presentation. Diagrams are two-dimensional line representations, usually intended (in old technology) for line block or line plate reproduction. They often employ symbols or simplified blocks to represent the objects or functions involved.

These symbols may be the subject of standards or specifications, with strictly formalised sizes and shapes. Many symbols now come as part of specialist software to ease the workload — the old-fashioned rub-on transfer is still used in some cases, though, but rarely at top level. Symbolic diagrams include graphs, maps, charts, hardware and functional drawings, circuit diagrams and flowcharts. Diagrams are useful in the presentation of statistical, symbolic or functional information. But more elaborate forms are needed for an adequate depiction of engineering hardware.

Line Illustrations
The commonest illustrations for equipment in technical documentation are line perspective drawings. These pictorial drawings are designed to convey the shape of objects and the position in space of the relevant parts. They may also illustrate the components used in assemblies and sub-assemblies, and the way they fit together and come apart.

Line illustrations are reproduced in a single solid colour with no tonal distinction. They may be black and white or coloured, using a mechanical tint, stippling or hatching, which simulate a variety of tones.

In the old technology, which you may still come across — hence our interest here — most illustrations were produced “twice up” on a Bristol board or even linen, by tracing over a pencil draft. Where modern technology is used the whole process is done on-screen, eliminating a number of the stages.

The term line illustration is used for any illustrative material which has no tonal variation, and which is suitable for simple line plate printing. Realism is often added to line illustration by means of perspective.

Next: 38. Perspective Drawings.

You will now need to prepare a work schedule to estimate the time likely to be needed for each step in the process. The main variable will be the number of times an author will have to go through each loop. Experience should give some indication here, but if not, it is certainly a wise practice to build in a contingency for perhaps two or even three trips around the course. An alternative would be to set a limit to this procedure, in agreement with the client, ensuring that some sort of draft is produced to time.

A straightforward time-based chart may then be constructed. For large-scale projects involving a number of volumes, the Project Evaluation and Review Technique (PERT), or the Critical Path Method (CPM) may be used. There is a lot of good software available now in this field. Approach a good supplier or, as usual, write to the Microsoft Campus in Reading. A general discussion of network analysis as these methods are called is given elsewhere under: Additional Subject Matter.

Next: 26. Costing.