Dear all and Elaine, I have an mrc volume of 450 x 450 x 450 px, put a marker at a particular location and cut out a box with 'Box around selected atoms with padding 60'. However, Chimera shows me the boxed volume as 124 x 123 x 124. I understand that the higher value must result from the voxel size being 0.97 A/px, so the dimensions would be 123.71 x 123.71 x 123.71 or anything similarly rounded. BUT why are the dimensions in x,y,z different and the box not exactly cubic? I noticed that it might have to do with centering but I do not understand how I can cut out a 'really' cubic box! Thanks for help, best, Dieter ------------------------------------------------------------------------ Dieter Blaas, Max F. Perutz Laboratories Medical University of Vienna, Inst. Med. Biochem., Vienna Biocenter (VBC), Dr. Bohr Gasse 9/3, A-1030 Vienna, Austria, Tel: 0043 1 4277 61630, Fax: 0043 1 4277 9616, e-mail: dieter.blaas@meduniwien.ac.at ------------------------------------------------------------------------