Piecewise affine (PWA) models serve as an important class of models for nonlinear systems. The identification of PWA models is known to be a difficult task and often implies solving a non-convex combinatorial optimization problems. In this paper, we revisit a recently proposed PWA identification method. We do this to give a novel derivation of the identification method and to show that under certain conditions, the method is optimal in the sense that it finds the PWA function that passes through the measurements and has the least number of hinges. We also show how the alternating direction method of multipliers (ADMM) can be used to solve the underlying convex optimization problem.