Constant-mean-curvature surface

Summary

A constant-mean-curvature surface, or CMC surface, is a surface in space whose mean curvature takes the same value at every point. Minimal surfaces are the case where this value is zero. CMC surfaces are the critical points of area among surfaces that enclose a fixed volume. So they model soap bubbles and other interfaces with a pressure difference. Round spheres and circular cylinders are the first examples.