iMol is a free molecular visualization application for Mac OS X operating system. The program is an indispensable tool for chemists and molecular biologists. iMol allows loading molecules using several file formats: PDB, MOL2, HIN, CAR, ALC, BIO. The molecules can be saved as PDB or BIO files. The BIO file stores all view and rendering settings (e.g. colors, lighting, orientation of molecules). iMol can easily handle both small and large molecules, it can load multiple molecules, move and rotate them independently.
The program can meaure distances, angles, and torsional angles between atoms. Molecules can be superimposed and RMSD (Root Mean Square Deviation) between atom coordinates can be calculated. Additionaly, protein chains can be structurally aligned to detect regions of high structural similarity. iMol can load multimodel PDB files and display them as a dynamics trajectory.
iMol uses OpenGL graphics to display molecules. The molecules can be rendered using various styles: wires, points, Van der Waals spheres, balls and sticks, polygons, strands, ribbon, cartoons, spring, tube, ladder. Individual atoms and/or residues can be selected and rendered independly. The rendering styles can be mixed up to visualize complex molecular systems in a more convienient way. There are several predefined color schemes available (e.g. residuum order, secondary structure, hydrophobicity), as well as custom colors. Also, different materials (e.g. plastic, metal, glass) can be used. The rendered images may be exported as a bitmap, as a PostScript file, or as a POV-Ray file.
Several rendering effects are available, including automatic rotation, motion blur, depth cueing (fog), background gradient, perspective, and stereo projection (using both side-by-side and red/blue anaglyph methods). Various rendering parameters can be fine-tuned.
