The Surface Evolver is an interactive program for the study of static surfaces shaped by surface tension and other energies. By definition it can solve the static Gauss-Laplace-Equation numerically, which determines the pressure difference across the surface. In most cases an analytical solution of the equation cannot be found, because it is an non-linear partial differential equation. The Evolver is the ultimate tool for static and fast solutions. Moreover, graphical output is available as screen graphics and several file formats, including PostScript.

A surface is implemented as a union of triangles, which is predefined by the user in a datafile. The program evolves the initial surface towards minimal energy by a gradient descent method. All defined energies, like surface tension, gravitation, rotation, user-defined energies, can be taking into account.

The program was devolved by the Geometry Center (K.Brakke, University of Minnesota) and is a public available free of charge program.
http://www.susqu.edu/brakke/evolver/evolver.html
At the same site you can also find a workshop for beginners from the Trinity College.