  The shape of materials is often subject to a number of geometric constraints
that limit the size of the system or fix the structure of its boundary. In soft
and biological materials, however, these constraints are not always hard, but
are due to other physical mechanisms that affect the overall force balance. A
capillary film spanning a flexible piece of wire or a cell anchored to a
compliant substrate by mean of adhesive contacts are examples of these softly
constrained systems in the macroscopic and microscopic world. In this article I
review some of the important mathematical and physical developments that
contributed to our understanding of shape formation in softly constrained films
and their recent application to the mechanics of adherent cells.
