Hi, I really like the animation panel of chimera because it makes it incredibly easy to create a nice looking movie, but transitions are still a bit limited compared to what one can do in a script - e.g. smoothly transitioning from one contour level to another, moving along a chain and highlighting specific residues, etc. On the command line, it is easy to do this and a bunch of other iterative processes using the “perframe” command. Perhaps it might be worth considering inclusion (in ChimeraX presumably) of an equivalent of the “perframe" command as an action in the animation GUI (One could call it “Custom” or “Script” to avoid confusion), to enable mixing in code snippets into the animation GUI? It would only need to have a couple of parameters - the frame range, variable range, interval, and command to execute (with a checker to catch invalid syntax prior to execution). Alternatively/additionally, it would be nice to have the option to export the current animation setup as an editable script, to provide a starting point for a more complex movie, although I am not sure whether this is feasible given the way the animation tool incorporates scenes. Cheers, Oliver.