Thanks Eric, that works perfectly! Now I use the following alias in my startup file:

alias ^rama2bfac ramachandran assign $1 ; setattr r ramaProb 1.0 :/^ramaProb ; open ~/Dropbox/chimera_startup/b_fac2rama.py

and it does exactly what I want.

Thanks!

OIiver
On Aug 26, 2014, at 2:39 PM, Eric Pettersen <pett@cgl.ucsf.edu> wrote:

from chimera import openModels, Molecule
for m in openModels.list(modelTypes=[Molecule]):
for a in m.atoms:
a.bfactor = a.residue.ramaProb