Pete gives a concise definition, but more here at Wiki -
https://en.m.wikipedia.org/wiki/Lofting

I have minimal experience laying down lines for a couple of cold molded skiffs,
but the same method is (was) used for much bigger vessels such as the Titanic.

You have a table of measurements (offsets) that in my simple case show the
distance marked from a baseline. The baseline is divided into stations. The
offsets measure from the baseline perpendicularly to a point. For any particular
line, says the top edge of a hull, you end up with a line of points, through
which you draw a fair line, using a flexible batten. You end up with the side
view of the hull and cross section views of the hull at each station. Hopefully
I didn’t embarrass myself too much with a description that’s clear as mud and
may be questionable on any number of points.

Phil

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