Thanks Elaine! This is exactly what I want. 
=============
# save current view settings 
view save my_view_name

# move to another position, zoom in or out, and color some residues etc

# get back to the original view in 20 frames along a STRAIGHT line
view my_view_name 20
=============

In the 20 frames of transition time, I can not do anything now. Is it possible to do something during the transition, like changing the surface transparency? Can we save the view matrix, devide the transition into many steps, and  do something else ( not motion-related, but coloring-related, etc) at each step?
Steve


On Wed, Feb 20, 2019 at 7:45 PM Elaine Meng <meng@cgl.ucsf.edu> wrote:
Hi Steve,
Not sure if it will solve the problem, but you could try saving views (“view save”) of the desired start and end positions, possibly also intermediate positions, and then use “view” with frames argument to gradually transition from one previously saved view to the another.  Saved views and their names are included in saved sessions.
Elaine

<http://rbvi.ucsf.edu/chimerax/docs/user/commands/view.html#name>

> On Feb 20, 2019, at 4:30 PM, Steve Chou <stevezchou@gmail.com> wrote:
>
> Dear ChimeraX team,
> Thanks for your fast and detailed responses to my questions!
>
> If a spot is in the center of view, we can zoom into the spot through a straight line. If it's not, it's really difficult to get there through a straight line.
> I tried something like this in a "movie" script, but it's still not straight.
> =========
> move y -20
> zoom 1.25
> wait 2
> move y -20
> zoom 1.25
> wait 2
> move y -20
> zoom 1.25
> wait 2
> =========
> Is there a way to zoom into a spot that is not in the center of view through a straight line.
> Steve
> --
> Steve Chou
>
>
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--
Steve Chou