[rDock-list-def] modify/use another force field for ligands

[Jose M. G. <jos...@un...>]

Dear rDock community,

After docking molecules containing NH2 attached to aromatic ring (sp2 
nitrogen),  the two hydrogens are not in the same plane as the N-ring. I 
believe this issue came from the force field.
I therefore analysed the force field used in rdock and noticed that 
several force fields are actually mentioned (in $RBT_HOME folder):
- masses.rtf : Insight97and Charmm27
- in folder sf, files Tripos52 (dihedral.prm, vdw.prm, vdw.prm.old)

I think Tripos52 is applied to the receptor (correct me if I'm 
mistaken), but what for the ligand?
How are used the parameters extracted from Charmm27 and Insight?

Secondly, I would like to know if it's possible to modify/use another 
force field instead of the one implemented in rDock for ligands?

Thank you for your help!

Jose Manuel