Hi, I have been 'opening' a python script file from within Chimera to start a session and in that script I open the MovieDialog manager (mdm) and read in a pdb with a series of models to be viewed as a trajectory. That part is working thanks to help from other responses in chimera-users. To modify the molecule (color, etc) it seems like the mdm.ensemble.molecule is giving me the access, though that may not be the right approach for my needs, because it seems to act on all frames. What I would like to do, from within this same initial python script, is to apply/register a perframe (also in python) script to control things like color on a frame by frame basis. I would like to do this as a way of keeping all of the setup in a single script file such that then I just need to record the movie manually, or perhaps there is a way to do this also from the script. Thanks much for any help and/or direction to documentation on the python api to the MovieDialog that allows control of these functions. Kersey