Visualization was essential for the development of this project. The complicated geometries of the crystal surfaces and point defect configurations inside the bulk, and the correct implementation of periodic boundary conditions are best tested by visualization tools. Once the simulation programs were prepared and debbuged, the visualization of the intermediate and final states helped identify phenomena suitable for a quantitative studying. In one word, it may be stated that "a picture is worth a thousand words".
The Atomic Visualization package (AViz) was used extensively in all stages of this project. Our computational physics group developed the AViz package . This is a very powerful visualization tool which helps to enhance the 3D perception. It includes a lot of various options, which let one to rotate the still sample, change relative sizes of atoms, create animations and movies, add and remove the bonds and borders of the sample, use color coding, slice of the sample and much more. The user-friendly interactive interface (See Fig. 3.2) simplifies the use of all these options in the visualization of computer simulations.