This article presents the refl ection on optimum design in one layer lattice shells to cover large span spaces with different base geometries. The objective is to fi nd parameters of form that have more effect on cost, in agreement with the Theory of Design of Structures (3,4), comparable to plane structures (4,12). To reach this aim, a program (8) has been created using Simulated Annealing (SA), a numerical approximation algorithm that fi nds solutions near optimum. The objective function used is extracted from the Theory of Design of Structures: structural volume. Its defi nition and characteristics will be seen. Diverse solutions to the numerical proposed examples are shown. These solutions solve similar problems changing the form of the plant to be covered. To fi nish, parameters of form from found solutions are displayed, and conclusions are extracted, such that SA is an appropriated method for this kind of problems.