Align coordinate system to marker, point or camera

[mcstieg]

Hello,

I try to rotate a model a given amount of degrees around x and y axis. 
The python script for rotation around any axis is already working.

The Problem is, that the second rotation will result in an unwanted change of the first angle.

Example:
- We have 3 given Markers on a flat surface. 1 & 2 are horizontal and position 3 is anywhere on the surface.
- We also know the real angle between markers 1-2 and 2-3 because we measured them ... -20 degrees and +30 degrees.

If I rotate -20 degrees around vertical axis, 1-2 are perfectly matching -20 degrees.
How can I rotate the model now to reach a +30 degree angle between 2-3?

Thanks a lot!!!!!

[Alexey Pasumansky]

Hello mcsteig,

Do you mean that you would like to perform the rotation around any line that should be defined as a pair of markers?

[mcstieg]

Dear Alexey,

sounds like what I am looking for ... 

[mcstieg]

...if you have any information on how to calculate this - I would be very happy! Thank you!

Just found out how to calculate the rotation matrix for any axis and a given angle. Now I need to calculate the rotation angle only. But I think this should possible somehow.

Thank you!