Forgot to reply to list as well.
    
    -------- Original Message --------
    
    
    
    On 11/25/2010 06:29 PM, Dennis Kolva wrote:
    > I have been using Chimera to export .stl files of proteins and
    RNA for 3D printing. The surface models print OK, but sticks or
    ribbons choke the printer. I looked close at the output meshes, and
    they have many extra surfaces which should be removed to make
    "legal" .stl format.
    >
    > Is that portion of the code open source? I'd like to take a
    closer look and see if it's possible to fix. It would be much easier
    to rectify the bad surfaces upon creation, rather than trying to
    remove them by post-processing.
    >
    > Thanks,
    >
    > Dennis Kolva
    > Cornell U.
    
    Presumably , you don't have a Z-Corp printer and their ZPrint
    software, 
    otherwise you would output VRML from chimera and have ZPrint do the
    
    proper conversion to STL.
    
    So yes, the source code is available at 
    http://plato.cgl.ucsf.edu/trac/chimera/browser/trunk/apps/x3d2/stl,
    and 
    we would welcome improvements. I believe that the problem is that 
    chimera does not output manifold geometry and that the X3D to STL 
    converter would need to perform CSG operations on all of the
    geometry, 
    especially the spheres and cylinders, to eliminate interpenetrating
    
    surfaces. Another issue to consider is what to do about ribbons and
    
    cylinders that are too thin for the printer you're using.
    
    Feel free to contact me directly with questions about the code or
    use 
    the chimera developers mailing list, chimera-dev@cgl.ucsf.edu,
    
    Greg