Hi Mauricio,
Thanks for your note. In the current version of v2.0, the system call is as follows:
system("pymol -c $pmlfile 2&> x3dna_r3d_pymol.msg");
i.e., with the -c option to run pymol in command-line mode. If I remember it correctly, I added this -c option following your suggestion (thanks!), while you and Guohui helped verifying the recipes for the 2008 3DNA Nature Protocols paper.
I understand what -q means, and could add it to 3DNA v2.0 as you suggested (i.e., -qc). Does it really matter? What differences does it make: -c vs -qc? Could you have a try and report back?
While 3DNA is distributed in binary form for C programs (per Rutgers license policy), the Perl scripts are actually open source. It has been my intention to keep it that way so that users can follow the examples, make changes as needs arise, and create new tools.
Xiang-Jun