Computational material design has gained considerable interest, along the last years, in the computational mechanics community. Although most of the current approaches focus on one-scale structural optimization, this work is settled in a multi-scale framework. In this sense, the goal consists of designing the micro-structure material and the macro-structure topology such that some cost function is minimized. In this case, the structural compliance is the considered cost function, so that the structural stiffness is maximized for a given weight.