A lecture given by Gautam Anand, at the Adventures in the Physical Metallurgy of Steels (APMS) conference held in Cambridge University. About the use of finite element methods to model the development of microstructure. Physical metallurgy concerns microstructure-property correlation. In this approach, microstructure evolves as the product of interactions between composition and process parameters controlled by the thermodynamic and kinetic conditions. Attributes concerning the property are obtained as the function of volume fraction, size, shape and distribution of the constituent phases, usually described through empirical relations or even on the basis of imprecise knowledge. Hence, the approach is more evolutionary than constructive. Performance driven construction of the microstructure demands precise response and interaction of microstructural constituents under the given loading condition. An architecturally designed microstructure implies planning, design and construction of microstructure considering nature, size, morphology and distribution of the constituent phases on a suitably conceived topological framework. With the aforesaid ambition, an attempt has been proposed on construction of the ferrite-martensite microstructure, based on iso-strain architecture, aiming at maximum work hardening. In another attempt, the mechanical response of a topologically designed bimodal microstructure in single phase steel has been evaluated for maximising the strength-ductility combination.