Visualization of core-code capabilities and standard time-stepping loop of MoCSI. Optionally executed functionality is marked as (opt.). The core code mainly provides utilities needed for the simulations. It loads shape models, generates the grid from user specifications, loads and creates snapshots as restoration points, and provides infrastructure such as matrices and solvers for linear systems of equations. The time-stepping loop is shown in detail. It consists of the outer time-integration loop and an inner iteration loop, which is used when nonlinear terms are present within the equations. If active, the steps marked in red are executed, and a check of the change in temperature against a user-specifiable abort criterion, ε, is done after every inner iteration; if the difference is larger than this criterion, it is redone, but with the modules in the pre-time step having access to the previously calculated temperatures.