VisualTAPAS is a self-contained, user-friendly, graphical user interface based simulator of wetetching and deep reactive ion etching with multi-masking capabilities, built upon an octreerepresentation of the silicon substrate (www.fyslab.hut.fi/∼mag/VisualTAPAS/Home.html).The program allows the use of a wide range of kinetic Monte Carlo (KMC) and cellularautomata time-evolution algorithms, including a fast octree search algorithm for the KMCsimulations. ‘VisualTAPAS’ stands for ‘visual three-dimensional anisotropic processing atall scales’. The use of the term ‘visual’ stresses the interactive visual capabilities of theprogram.Here, a brief history of the evolution of VisualTAPAS as a research tool willbe presented: from the initial efforts, explaining the anisotropy of wet etchingas a result of steric hindrance using a combination of density functional theory(DFT) and KMC simulations, to the most recent implementation, focusing on thepropagation of the etch front for engineering applications by making use of theanalytical solution of the continuous cellular automaton (CCA) method; and inbetween, a recent example of DFT assisted understanding of the effects of metalimpurities on the surface morphology of the etched surfaces will be presented.We try to bridge together three complementary simulation tools, namely, DFT,KMC and CCA methods. Our experience with the use of the three methods forthe simulation of anisotropic etching shows that DFT is very useful and, manytimes, an unavoidable approach. Similarly, the KMC approach is the method ofchoice for understanding the large variety of etched surface morphologies while theCCA is an outstanding tool for the simulation of the process at an engineeringlevel.