[Chimera-users] Euler angles and rotations

[Elaine Meng]

Hi Stephen,
In Chimera, you can write the current transformations of models to a file with "matrixget" and apply transformations from those matrices by  reading the file with "matrixset."

<http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/matrixset.html>

It doesn't have anything to do with Euler angles, though.  Not sure if it suffices for what you want to do.

To send a question for all staff to see, it is best to use the mailing list CC'd here.

For ChimeraX, there is similar stuff in the "view matrix" command and saved "positions" files.  However, the positions file doesn't include camera position, so in my opinion is not quite as useful for regenerating the view as matrixget(set) in Chimera.
<http://rbvi.ucsf.edu/chimerax/docs/user/commands/view.html#matrix>
<http://rbvi.ucsf.edu/chimerax/docs/user/formats/positions.html>

Best,
Elaine
-----
Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco


> On Sep 16, 2020, at 12:04 PM, Chin-Bow, Stephen <stephen.chin-bow at yale.edu> wrote:
> 
> Hello Elaine,
> 
> I have a math question which hopefully you or the CGL staff can answer quickly.
> 
> I am using the original Chimera (although I recently upgraded my GPU and I am curious to try ChimerX ).
> 
> I am curious about Euler angles and rotations.  I would like to learn more about them, but I suspect it has been too many years since I thought about matrices.
> 
> I want another person to first download a published PDB from the RCSB before rotating it using a command line script.
> 
> The final perspective I have was achieved after ten rotations.
> 
> Is there a way I can apply Euler angles and matrix multiplication to summarize the final position using the fewest number of rotations?
> 
> Yes, I can simply share a session file, but my future goal is more general.  I want to encourage the other person to learn to use scripts, because the command line opens up the power of Chimera.
> 
> Thanks a lot for the remedial math help!
> 
> Stephen