We present a method relying on expansion textures to add details such as folds on a surface. The user paints the expansion attributes on the surface (amount and direction of expansion, wavelength and regularity of folds), using either interactive or procedural tools. The modeling system generates the folds by calculating the new surface equilibrium. Results show that this tool allows CG artists to easily control the aspect of folds and drapes by adding surface locally, which is close to the way sculptors think. Our original contribution does not lie in the equilibrium solver, but in the very principle of texturing expansions to specify shapes details.