Page 74 - Between light and shade

between light and shade, TRANSPARENCy and reflection

canopies” for architecture, in the 1960s, and
methodically developed the grammar and voca-
bulary for them. He specifically studied various
minimal surfaces made possible with the aid of
a film of soap on a closed contour 77.

The material of these surfaces (still with
a negative Gaussian curvature, except for the
plane) with a constant thickness is subject to
constant stress in all directions at all points.

It is impossible to find more efficient forms
for supporting their own weight, but they are not
all efficient at absorbing the other loads to which
the membranes are subjected. What is more,
tents are always made from assembled strips of
fabric and formed from a weft and a warp thread
with different strengths (σ) and stiffnesses (E)
in both directions 78. Therefore, this minimal

structures, paradoxically heavily encumbered by their fittings,
have subsequently been very rarely used except for a few large
aviaries. Nevertheless, in 2009, they gave me the idea of nets
made from sewn para-aramid rope.
77 It was the Belgian physicist Joseph Plateau (1801-1883) who
carried out the first research into minimal surfaces with the
aid of films of soap resting on a metal wire. He discovered the
minimal surfaces of revolution under internal pressure (with
a constant mean curve, not zero as demonstrated by Charles
Eugène Delaunay (1816-1872)): the plane, the sphere, the cylin-
der, the catenoid, the onduloid and the nodoid. See also the
works of D’arcy Wentworth Thompson, including On growth
and form, Cambridge University Press, 1917.
78 Except for “pre-stressed” polyester — PVC fabric, invented by

Serge Ferrari, in Lyon, in 1973.

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