Hi all, I’ve noticed there seems to be a bug/limitation in rigid body fit in Coot when applied to large selections at low resolution - I have noticed this most frequently on EM maps, but it is also appreciable for low resolution crystal structures.
It is fine on small regions, but when applied to the whole molecule or large domains it actually seems to make the fit worse, even if it was pretty good to begin with (e.g. when I have already conducted rigid body fitting beforehand in another program, such as chimera or phenix). To reproduce, try “Rigid body fit molecule” on PDB 4WL1, against the map from the EDS, or for a higher resolution example with the same behaviour, try 4QSL (both without applying any initial displacement). Cheers, Oliver.
