Dear Yan, Sorry, you cannot do this. 3D classification with a single class is much more tunable. You could use this to 'pre-center' your particles better, and then use that data.star as input for an auto-refine. HTH, Sjors > Hi Sjors and all, > > I was wondering whether or not it's possible to modify the value of offset > range when continuing 3D refinement, like using greater offset range and > finer offset step. I knew that, in general, when one continues 3D > refinement the options of --offset_range and --offset_step are invalid > arguments. But I hope there is a way to do that. > > All the best, > Yan > -- Sjors Scheres MRC Laboratory of Molecular Biology Francis Crick Avenue, Cambridge Biomedical Campus Cambridge CB2 0QH, U.K. tel: +44 (0)1223 267061 http://www2.mrc-lmb.cam.ac.uk/groups/scheres