I couldn't find any Tcl code for manipulating data for a 3d printer so I started "frusta".
I used fossil as the VCS, and hosted it at chisel (http://chiselapp.com/user/seadevil/repository/frusta/index )
As of version 0.0 it can read ASCII STL, and ASCII gcode and draw those objects in a canvas3d (Which does all the heavy lifting)
I plan to write some Tcl script functions to analyze the 3d objects. Any feedback or help is appreciated. If you think I'm going the wrong directions with it feel free to fork it.
dzach 2013-11-4 I'm very much interested in the gcode viewer and the fast 3D canvas! Got some errors while parsing some gcode files, but that's just version 0.0 :) Also, I cannot view gcode files intended for milling, maybe because there is no extrusion taking place?
EDIT: I got rid of the gcode errors by commenting out the error command in proc unknown in the gcode.tcl package.