Thank you, Tom. It is good that command matrixget can fix the problem. ----------------------------------- Hi Guiqing, The "fit model in map" and "fit map in map" tools (menu Tools / Volume Data) report the relative translation and rotation of two models. But if you are not doing a fit I don't know of an easy way to get that information. There is the "matrixget" command that writes rotation and translation matrices (3 by 4 matrix) for each model but that would require some calculation to extract a rotation angle and translation. Do you want the relative orientation between two models, or just the absolute orientation of a single model on the screen? What center of rotation do you want? If you choose a different center of rotation then the displacement is different. A pretty simple Python script could give the desired information. I've attached an example script that you can open in Chimera (use File / Open) to report the relative position of two models. Tom ----------------------------------------------------------------