[chimera-dev] Changing guide atom

Hello list, I'd like to change the guide atom in res.ribbonData to use O instead of CA as an example. Here is what I did: for r in mol.residues: for a in r.atoms: if a.name == 'O': r.ribbonData.guide = a # Set O as guide Atom if r.isHelix: # Update the display r.ribbonDisplay = True r.ribbonDrawMode = chimera.Residue.Ribbon_Round This does not seem to redisplay/recompute the helix through O Atoms. I am not confident with the way I altered the guide Atom or is it another problem like updating the ribbon or so... If someone can help... Thanks to all PL