Thank you both. Works like a charm. I like the solution with the rotation being defined by which side of the bond one clicks – that is exactly the type of thing I need. It gives me an error when I accidentally click at the center but I can live with that and just have to be careful with my selection. Thanks again, Józef From: Eric Pettersen <pett@cgl.ucsf.edu> Date: Friday, 6 December 2019 at 23:19 To: Tom Goddard <goddard@sonic.net> Cc: "Lewandowski, Jozef" <J.R.Lewandowski@warwick.ac.uk>, "chimerax-users@cgl.ucsf.edu" <chimerax-users@cgl.ucsf.edu> Subject: Re: [chimerax-users] Rotate bond move large/small option in VR On Dec 6, 2019, at 3:11 PM, Tom Goddard <goddard@sonic.net<mailto:goddard@sonic.net>> wrote: br = self.session.bond_rotations.new_rotation(pick.bond) br.moving_side = br.bond.other_atom(br.moving_side) # Move the large side Not sure why this was hard to find since it’s a documented arg of new_rotation, but just do this: br = self.session.bond_rotations.new_rotation(pick_bond, move_smaller_side=False) —Eric Eric Pettersen UCSF Computer Graphics Lab