Hi Duncan, Chimera uses a 3 by 3 rotation matrix and a shift vector to describe the position of the models. You can use the matrixget Chimera command to output those matrices for each model to a file. There isn't currently a command to show rotation angle / axis / shift although the Fit Map in Map tool (Tools / Volume Data / Fit Map in Map) reports this information in the Reply Log. If you are not using that fitting optimization code you could call its Python routine to print the rotation angle / axis / shift information using the attached Python script. The attached script assumes there are only two models currently open in Chimera. I tested it with Chimera version 1.2468. Tom # Chimera script to report the relative orientation of two models. # Get two models. Assumes only two are currently open. from chimera import openModels m1, m2 = openModels.list() # Calculate relative transformation. xf = m2.openState.xform xf.premultiply(m1.openState.xform.inverse()) # Print transformation to reply log. from PDBmatrices import xform_matrix from FitMap.gui import transformation_description print transformation_description(xform_matrix(xf)) # Show reply log window. from Accelerators.standard_accelerators import show_reply_log show_reply_log()