How to rotate a 3D cylinder to a straight up position

I have few tall cylinder-like 3D objects (in different files) pointing to different directions and I'd like to 'straight them up'. Is there a quick solution to do this?

[Jan]

It depends on how the coordinates are store in the files and what "straighten up" exactly means. What exactly is "quick"? Programming time or run time?

[khcy82dyc]

thanks for the reply! I'm hoping to rotate the objects so they look like all stand up straight.

I'm using the following functions to get the unit vector and rotate it in the opposite direction but the results come out a bit wrong:

   stat = regionprops3(original3D,'MajorAxis'); 
   rotated3D= rotImg3(double(original3D), 1*pi/2, 0-stat.MajorAxis);

from

https://uk.mathworks.com/matlabcentral/fileexchange/47578-regionprops3 https://uk.mathworks.com/matlabcentral/fileexchange/44990-3d-rotation-of-3d-image