The comprehending of the processes’ physics is a prerequisite for the purposeful design and optimization of digital fabrication systems, as well as their efficient and robust process control. This chapter presents an overview of the underlying physics relevant to an understanding of the processing of cement-based materials during various production steps of digital fabrication. In this, the main focus was on various approaches of Additive Manufacturing, but selected aspects of formative processes were addressed as well. For some processes, analytical formulas based on the relevant physics have already enabled reasonable predictions with respect to material flow behaviour, buildability, and other relevant features. Nevertheless, further research efforts are required to develop reliable tools for the quantitative analysis of the entire process chains. To accomplish this, experimental efforts for the characterization of material properties need to be accompanied by comprehensive numerical simulation. The presented work results from collaborative research carried out by the authors in the framework of the RILEM Technical Committee 276 “Digital fabrication with cement-based materials”.