Hi, After compiling therion model viewer, I found something has changed, so I post this to get it recorded: We need: tcl/tk8.4 installed (if you are on debian, aptitude install tcl8.4-dev tk8.4-dev) (as root) ln -s /usr/include/tcl8.4/tk.h /usr/include ln -s /usr/include/tcl8.4/tcl.h /usr/include ln -s /usr/include/tcl8.4/tclDecls.h /usr/include ln -s /usr/include/tcl8.4/tclPlatDecls.h /usr/include ln -s /usr/include/tcl8.4/tkDecls.h /usr/include (may be I need this linking because I have both tcl/tk8.3 and tcl/tk8.4 installed) (as user) cd /path/to/therion/sorce/thtom/linux make su cp -R Tom0.2 /usr/lib/tcl8.4 exit done; you can run xtherion as user now and see if there is model wiewer window (it should) Previously (0.3.8 or so) I copied Tom0.2 to /usr/lib/tk8.4, but it seems not to work anymore. Regards, Roman