Working Drawings Handbook
work on the project at different times and on different
computers. It is also possible that on more complex
projects creation of the production information set will be
shared between different professionals working in
separate offices. The traditional method of exchanging
data and coordinating various aspects of a project would
have been to send marked up prints back and forth
through the post, with separate sets of drawings being
produced as the final design emerged.
In model exchange, where all the professionals are
using CAD to produce their drawings (ideally but not
necessarily the same CAD program), it is the ‘model’
that is sent back and forth on disk, CD or by email rather
than pieces of paper through the post. Hopefully, the
final scheme is better coordinated, with fewer errors,
omissions and conflicts. Management procedures must
be in place to ensure that everyone is working from the
same version of the CAD model, but in theory at least, a
better set of production information should be created,
with far less duplication of effort.
Manual drawing
This has now been largely superseded by CAD. The
most recent RIBA survey indicates, however, that 15 per
cent of small practices still draw the bulk of their work
manually, and it seems desirable therefore that some
notes be included covering the method of elementalising
drawings manually.
The method is very similar in essence to the CAD drawing
overlay method described previously. A basic floor plan is
drawn (see the section entitled ‘the basic floor plan’ in
Chapter 2) and from it are taken the requisite number of
copy negatives (normally by dyeline reproduction on some
translucent medium which will take manual drawing on its
top surface). The elemental information is then added to
each copy negative, which is then coded elementally and
printed for inclusion in the drawing set.
The use of copy negatives is really only applicable to
general arrangement drawings. Even in situations where
an assembly or component drawing has been given an
elemental CI/SfB coded number it is unlikely to have
benefited from the superimposition of additional layers of
information and might as well have been produced as a
single sheet, drawn once only.Paper size is of less consequence here than in the other
methods discussed, for the production of the negative is
limited only by the size of the drawing board available
and the cost implications of using large drawings are not
so great as they are with more sophisticated methods.
Nevertheless, the same general comments regarding
paper sizes which were made earlier still apply with
manual draughting. No one is going to think kindly of
you while trying to consult an A0-sized drawing flapping
about in a gale on an exposed building site.As to the medium upon which manual drawing may be
carried out, there is a wide range, coupled with a range
of pens and pencils.Materials for manual draughting
Detail paperhas the great advantage of being cheap
and, because it offers a semi-opaque background,
pleasant and satisfying to draw on, particularly in pencil.
It is best suited to the preparation of drafts for
subsequent tracing into final drawings, where the
original sheet may be expected to have a limited life,
and where any prints taken from it will be for internal
exchange of information among team members, and
also for rapidly produced pencil details (accompanying
architects’ instructions, for example).Tracing paperis the most common medium in use today.
A smooth finish is desirable, especially for pencil work,
where the more abrasive surfaces of the matt and semi-
matt finishes tend to wear down pencil points rapidly
and are more difficult to keep clean during the
preparation of the drawing. A weight of 90 g/m^2 is