Hi Wendy, The "Offset" field in the EMANimator spin settings controls the center of rotation. I don't see any option to put the rotation center at the center of the molecule. It looks like the only approach is to type in the numeric coordinates for the center. (This tool was written by Steve Ludtke so I do not know all its nuances.) Here's how you can figure out the right values. Select some or all atoms of the molecule which will be used to compute the center of rotation. Use menu entry Actions / Set Pivot. The rotation center coordinates will be shown in the status line at the bottom of the Chimera main window (and in the reply log, menu entry Favorites / Reply log). Use the negative of those coordinates for the offset field in the Spin settings. If you only need to spin a molecule around you could make a movie with the Chimera Movie Recorder instead of EMANimator. Make a Chimera command script like: movie record roll y 3 120 wait 120 movie stop movie encode mformat mov output /usr/local/src/staff/goddard/test.mov in a file movie.cmd and open movie.cmd in Chimera. EMANimator is better for composing more complex movies. Tom