Hi Joe, (A) One idea is to use “define axis,” e.g. open 2mnr define axis protein <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/define.html#axis> Reply Log gives: axis name, ID, length, center, direction: axis: a1 63.317 ( 30.664, 11.322, 12.737) (-0.566, -0.439, 0.698) (B) Alternatively, “measure inertia” to get principal axes, e.g. measure inertia protein <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/measure.html#inertia> Reply Log gives: Inertia axes for 2mnr 2698 atoms v1 = -0.565 -0.435 0.700 a = 33.352 r1 = 13.200 v2 = 0.611 0.349 0.710 b = 22.381 r2 = 17.220 v3 = -0.554 0.830 0.069 c = 19.243 r3 = 17.962 center = 30.353 11.093 13.054 (a,b,c are half-diameters) Axis is a little shorter than first principal axis, will look into that. (C) For bounding box aligned along X,Y,Z see this previous post: <http://plato.cgl.ucsf.edu/pipermail/chimera-users/2008-April/002540.html> I just tried it to make sure it still works. I put the lines in a file named box.py, then opened a PDB file, then opened box.py. The box was shown in the graphics window and the dimensions reported in the Reply Log. However, this is just a box aligned with X,Y,Z, so it’s not really the molecule dimensions (the molecule could be diagonal within the box). Also, apparently it depends on what is displayed, so you should display all the atoms you want in the calculation and not the ones you don’t, like solvent. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco
On Jun 18, 2018, at 6:13 AM, Healey, Joe <J.R.J.Healey@warwick.ac.uk> wrote:
Hi Chimera Team, Is there a quick/automatic way to determine the largest dimensions of a model (maybe its minimal bounding box or similar?) without having to select 2 atoms specifically to draw the distance between? Thanks
Joe