Hi Greg, Sounds neat. Will a multi-touch interface work with a standard laptop touch-pad? The source code for Chimera is on the web though it isn't up to date. http://www.cgl.ucsf.edu/chimera/sourcecode.html All of the functions you are interested in are implemented in Python code which is included in the distributed Chimera. The Python code is in files (with ".py" suffix) in directories under chimera/share or on Mac under directory Chimera.app/Contents/Resources/share. But it is quite difficult to find the Chimera Python routines you need. Our programming reference guide (automatically generated from code comments) is not too useful but we provide programming examples that might help. http://www.cgl.ucsf.edu/chimera/docs/ProgrammersGuide/Examples/index.html The easiest approach is to ask us by email for the routines you need, e.g. list all chain identifiers, select chain given id, color equivalent to actions menu, move models, rotate models, show atom-atom distance, find atom under mouse, draw label.... Eric Pettersen is the most familiar with that code and what simple routines already exist to do those things. He is on vacation now but expected back around Thursday. You are interested in atom-atom distances. Will the user choose an atom through the touch interface? It seems that would require visual feedback in the Chimera window -- equivalent of the mouse pointer. I suppose you could take over the mouse pointer, or you could create a new "cursor" implemented perhaps as a Chimera 2d label. Tom