The use of computer software to produce simulations of molecular structures. Various chemical drawing programs exist to allow a graphic representation of chemical formulas in two dimensions. More sophisticated three-dimensional modelling programs also exist. The information about the molecule is stored in a data file giving the numbers and types of atoms present and the coordinates of these atoms. The software converts this into an on-screen three-dimensional view of the molecular structure in some specified format (e.g. ball-and-stick, wireframe, etc.). The structure can be rotated on the screen and, depending on the software, calculations may be done on the molecule.