WORKING DRAWINGS HANDBOOK, Fourth Edition

Drawing the set

symbols or component drawings from menus and insert
them in your drawings where needed. The more
sophisticated programs will add the inserted
components to automatically generated schedules.

Several generic block and symbol libraries are available
for sale, some with CAD versions of diagrams from
books that you can insert straight into your drawing
files. These are designed to give you some of the
benefits of dedicated architectural packages at a much
lower cost (4.9).

One long-term aim of the building industry is that
manufacturers start to provide libraries of intelligent
‘objects’ rather than simple blocks. The task is immense
and although the dedicated architectural CAD programs
already use ‘objects’ it seems unlikely that we shall see
any substantial number of ‘object’ libraries in the near
future.

The final source of block and component libraries is to

create your own. A not inconsiderable advantage of

creating your own libraries is that quality is ensured.

A disadvantage with some low cost libraries is that they

were produced, seemingly, by very junior staff and not

checked thoroughly before distribution. At least you

know your own libraries are perfect.

It is not necessarily an onerous task to create these

libraries. They can be built up over the years by ‘writing out’

parts of drawings you create for use later on other projects.

Dimensioning

That this is a more complex subject than may appear at

first sight may be illustrated by a simple example.

Consider a timber window set in a prepared opening in

an external wall. Unless the wall is to be built up around

the window frame, in which case the frame itself will

4.8 Examples of plastic cut-out templates available commercially