Hi Jim, The Chimera C++ source code is available on request for outside developers. Most of the source code is Python which comes with all Chimera distributions. The Chimera C++ header files are also available. The link for those is in the Chimera Programmer's Manual (not on the download page). http://www.cgl.ucsf.edu/chimera/docs/ProgrammersGuide/index.html The Chimera C++ source code is currently provided by request. The C++ source is not freely available for reasons I do not understand. You would need to discuss that with the head of our lab Tom Ferrin (tef@cgl.ucsf.edu). There is one piece of code used by Chimera for computing molecular surfaces (MSMS from Michel Sanner) for which the source code is not available. Chimera depends on 25 third party packages (TclTk Togl Tix Pmw PyOpenGL zlib Python Numeric jpeg tiff freetype Imaging netcdf Scientific MMTK HappyDoc tr openssl ftgl omni msms otf autostereo swish-e FFmpeg), so it is quite alot of work to compile it yourself. So the main use to you of the Chimera source code is probably for figuring out how Chimera works -- not for building it yourself. Tom