crystal structure viewer

 DRAWxtl reads a basic description of the crystal structure, which includes
 unit-cell parameters, space group, atomic coordinates, thermal parameters or
 a Fourier map, and outputs a geometry object that contains polyhedra, planes,
 lone-pair cones, spheres or ellipsoids, bonds, iso-surface Fourier contours
 and the unit-cell boundary.
 .
 Four forms of graphics are produced:
 .
  * an OpenGL window for immediate viewing
  * the Persistence of Vision Ray Tracer (POV-RAY) scene language for
    publication-quality drawings
  * the Virtual Reality Modeling Language (VRML) for dissemination
    across the Internet
  * a Postscript rendering of the OpenGL window for those who want
    high-quality output but do not have POV-RAY installed.
 .
 File formats DRAWxtl can read include CIF, FDAT, FullProf (pcr), GSAS, SCHAKAL,
 SHELX, DISCUS and WIEN2k.