Due to the algorithmic simplicity, cellular automata (CA) models are useful and simple methods in structural optimization. In

this paper, a cellular-automaton-based algorithm is presented for simultaneous shape and topology optimization of continuum

structures, using five-step optimization procedure. Two objective functions are considered and the optimization process is

converted to the single objective optimization problem (SOOP) using weighted sum method (WSM). A novel triangle

neighborhood is proposed and the design domain is divided into small triangle elements, considering each cell as the finite

element. The finite element formulation for constant strain triangles using three-node triangular elements is developed in this

article. Topological parameters and shape of the design space are taken as the design variables, which for the purpose of this

paper are continuous variables. The paper reports the results of several design experiments, comparing them with the currently

available results obtained by CA and genetic algorithm in the literature. The outcomes of the developed scheme show the

accuracy and efficiency of the method as well as its timesaving behavior in achieving better results