However, as an engineer, I am pretty sure that if the finished clothes
are to be sized to the centimeter, the pattern pieces will need to be
cut to better than whole centimeter accuracy. Further, the practice is
that ALL engineering drawings (at least for things under 100 m) be in
millimeters, and I would interpret the pattern as an engineering
drawing. To the degree that sub-centimeter accuracy is required in the
pattern or cutting, I think that manufacturing in millimeters is
preferable to 0.1 cm. The finished product can still be labeled and
advertised in whole centimeter sizes.
What you say makes perfect sense. From the producer's prospective, it would seem more logical to
use mm in the design and cutting, but from the consumer's perspective, cm would be a more logical
choice to use in labelling.
I believe the choice of prefix comes down to:
- A prefix that results in whole numbers is preferable to one that requires the
use of decimals.
- A prefix that results in smaller whole numbers is preferable to one that results in unnecessarily
large numbers, or an unnecessarily exact precision.
The first would mean you'd choose 46 mm rather than 4.6 cm, and would mean where a greater precision
than 1 cm is required, mm would be the preferred choice (and this would therefore be the case in the
majority of applications).
The second would mean you'd choose a clothing dimension of 102 cm rather than 1020 mm, or a height
of 174 cm rather than 1740 mm *provided* you never need a precision greater than 1 cm. Note the the
first guideline would mitigate against choosing 1.02 m or 1.75 m (whole numbers preferable to decimals).
Tom Wade
