# [Chimera-users] Euler Angles

Tom Goddard goddard at sonic.net
Tue Jun 30 10:57:13 PDT 2020

```Hi Gabriella,

Euler angles are not rotations about x, y, and z.  Rotations about x,y,z and also Euler angles are generally not very useful for explaining relative orientations of domains because they are hard for a person to comprehend and depend on the coordinate system.  It is particularly tricky because the order of the rotations matters, for instance, a rotation of 30 degrees about x followed by 30 degrees about y is different from 30 degrees about y followed by 30 degrees about x.

So usually just the total rotation about the axis of rotation is reported and that is what Chimera tells you,

If you still want Euler angles or x,y,z rotations Chimera does not produce those and you will need to find other software to do it.

Tom

> On Jun 30, 2020, at 7:06 AM, Gabriella Angiulli <gab.ang87 at hotmail.com> wrote:
>
> Hi Tom,
>
> What I need to do is calculating the transformation (rotation and translation) of the same domain in two different conformations. Particularly, I would like to describe the rotation as rotational angles around the three axis (x,y and z). I know that Chimera provide for the rotational angle, but what I would like to know is the Euler angels.
> Thank you so much,
> Gabriella
>
>
>> On Jun 29, 2020, at 4:45 PM, Tom Goddard <goddard at sonic.net <mailto:goddard at sonic.net>> wrote:
>>
>> Hi Gabriella,
>>
>>   Chimera does not output and does not use Euler angles as described in this previous message
>>
>> 	http://www.cgl.ucsf.edu/pipermail/chimera-users/2017-November/014102.html <http://www.cgl.ucsf.edu/pipermail/chimera-users/2017-November/014102.html>
>>
>> What software are you using that wants Euler angles?  There are different conventions in how Euler angles are defined.
>>
>> 	Tom
>>
>>
>>> On Jun 29, 2020, at 8:36 AM, Gabriella Angiulli <gab.ang87 at hotmail.com <mailto:gab.ang87 at hotmail.com>> wrote:
>>>
>>> Hi,
>>>
>>> I’m trying to calculate the transformation between two Cterminal domains in two different conformations and I’ve been using the command “measure rotation”. The rotation is reported in the first three columns of a 4x3 matrix in the log file window and my question is: do I have a way to get the Euler angles of my transformation from that matrix ?
>>>
>>> Thank you so much,
>>> Gabriella
>>>
>>>
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>>
>

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