Forcefield variants and properties addition

[ethanev]

Hi, would it be possible to add functionality to use variants of MMFF and alter properties of the forcefield (I believe this would be implementing the Forcefield module)? I commonly need to optimize structures in different dielectrics and get energies like below (cids is just a list of ints for the conformers previously generated and mol is a molecule with generated conformers):

`
dielectric = 80.0
mp = AllChem.MMFFGetMoleculeProperties(mol, mmffVariant='MMFF94s')
mp.SetMMFFDielectricConstant(dielConst=dielectric)
ff = AllChem.MMFFGetMoleculeForceField(mol, mp)
AllChem.OptimizeMoleculeConfs(mol, ff, numThreads=num_threads)

for cid in cids:
ff = AllChem.MMFFGetMoleculeForceField(mol, mp, confId=cid)
e = ff.CalcEnergy()
`

Would it be possible to add such functionality? This would significantly impact my discovery workflow!
Thanks,
Ethan

[scal444]

Thanks for the feature request! It's something we could do some refactoring, similar to issue #26. It isn't our top priority this cycle but will discuss with the team since we have 2 requests for a FF module.

[scal444]

Hoping to have PRs to expand usability in the next week or so