In this chapter the current status of laser annealing simulation models, in the continuum formulation for the evolving fields (e.g., temperature, phases, doping density), is presented and discussed. The content is organized so as to gradually guide the reader from the basic principles to the formalisms already implemented in the Technology Computer-Aided Design (TCAD) tools for the laser processing and, finally, to the less studied features which can be the topics of future developments. The laser-matter interaction models are outlined and the thermalization approximation, on the basis of the TCAD models, is introduced in the right context. Within this approximation, self-consistent numerical solutions of the ultra-fast heating, induced by pulsed lasers in the nanoseconds time scales, are discussed highlighting the crucial differences between the solutions obtained in blanket and patterned 2D and 3D complex systems …