SMILE--shaded molecular imaging on low-cost equipment.

The SMILE program runs under MS-DOS on IBM PC AT-compatible computers equipped with the SM640 or the PG640 Matrox graphic board. The program allows real-time three-dimensional (3D) animation and modeling of several isolated molecules that can be built from scratch, manipulated interactively and compared by superimposition. SMILE enables users to compute atomic partial charges, molecular surface area, molecular volume, electrostatic and nonbonded potential energies. PLUTO, ORTEP, and MMP2 input files are set up automatically. The program also provides simple access to crystal packing by real-time animation of the unit cell contents, interactive inspection of the relevant stereochemical parameters and fragment manipulation within the unit cell. SMILE animates stereo views and produces beautiful shaded 3D images (8 colors, 32 shades each) of molecules in many different styles--stick, ball-and-stick, CPK (space filling), and transparent CPK with backbone.