Avogadro2 is a user-friendly molecule builder and editor. It offers flexible rendering and a powerful plugin architecture for developers. The program supports interactive building of molecules with integrated molecular mechanics and a fragment database. Input generation for GAMESS, MOPAC, or Gaussian calculations is provided. For visualization, the program supports crystallographic unit cells, isosurfaces and orbitals from Gaussian cubes and OpenDX.
Note: Now requires OS X 10.8 or later