Drawing the set
The use of this convention provides a ready mental
reference for checking the handing of any component
and for providing instructions to others. Like any other
convention, however, it is of little use to the recipient
unless they are in on the secret. So they must be told,
preferably by a simple statement at the start of the
component schedules.
The conventions determining window openings are in
more general use, presumably through the early
development of the metal window industry with its
requirements for off-site hanging of casements and a
consequent clear system for describing the handing.The normally accepted convention is that the window is
drawn as viewed from the outside. Conventional
representations for both door and window openings are
given in Appendix 2.Hatching The use of hatching of various kinds to give
a graphical indication of different materials was first
developed as a readily reproducible alternative to the
laborious colouring of opaque originals which had
preceded it.The existing ranges of conventions are based on
building techniques of a previous century, and were they
to be brought fully up to date an enormous expansion of
conventions would be necessary. Such concepts as
loose-fill insulation, for example, fibre-glass mouldings,
or glass-reinforced cement would all require
consideration.One should first question the necessity, or indeed the
desirability, of hatching in the first place. It should only be
used when confusion is likely to occur in the
interpretation of drawings, and in most cases such
potential confusion may be avoided by other means.
Building elements shown in section, for example, may be
distinguished from lines in elevation or grid lines by
affording each their proper line thickness, without
recourse to hatching. Different materials are less likely to
be confused with one another when drawings are
elementalised; and in any case, the mere differentiation
between, say, brickwork and blockwork, which is possible
with hatching, is not normally sufficiently precise for
present-day purposes. We want to know if the bricks are
commons, or engineering quality, or facings. We want to
know if the blockwork is lightweight for insulating
purposes or dense and load-bearing. Such subtleties can
only be covered by proper annotation and such
annotation will often render other methods redundant.4.7 Key to sub-divided plan forms part of the title block