Hi everybody, The value of the dielectric constant used by Chimera is 1, corresponding to calculations in vacuo. Is there not an easy way to change this value to, say 78 or to include a sigmoid function or the Generalized Born approach so as to mime the presence of the solvent ? I looked for it but couldn't find it : where in the {chimera_install_location}/share/MMMD/MMTKinter.py file can the value of the dielectric be changed ? Otherwise, how to mime implicitly the solvent ? Also, it seems that only the Steepest descent, and not the Conjugate gradients method, for energy minimization has been implemented in Chimera. Why is this so? It'd be so nice to have these two functionalities added as I don't know of any free academic program allowing us to do energy minimization with these options without having to parametrize every new ligand (Charmm, Namd), a painful task. Cheers, Charbel