This paper presents an original stochastic method of optimization (PGSL) for optimum design of truss structures. PGSL (Probabilistic Global Search Lausanne. developed at the Swiss Federal Institute of Technology at Lausanne) has been inter-faced with a finite element code. then applied and tested on several size optimization problems of plane truss structures. https://www.zodiacintl.com/product-category/reinwassersysteme-schlauchaufroller/