[Paraview] Rotation of a slice

[Alexander Berdnikow]

Hi all,

I am working on a python script to rotate a slice in the x-y-plane and  
can't find a way to compute the parameters for the Transform filter.

The slice is computed by a script and is defined by the origin and the  
normal. It looks like this:

https://www.pic-upload.de/view-33136320/slice.png.html

The origin is (12.65, 10.55, 3.0)
The normal is (9.28454496846, -68.7942219477, 21.4027743404)
or (0.127811549959, -0.947024993173, 0.294631753216) if it is normalized.

Now I want to rotate the slice in the x-y-Plane, so that the normal of  
the rotated slice points in z-direction.

I tried to rotate the normal-vector with the rotation matrices (  
https://en.wikipedia.org/wiki/Rotation_matrix ), but it does not work.  
The computed vector shows somewhere, but not in z-direction, when I  
set it in the Transform filter.

The right rotation input for the transform filter is approximately  
(-71, -19, 0) but I have no idea, how to get there by computation. The  
angle of the normal with the x-axis is about 82 degrees, with the  
y-axis about 161 degrees. I computed rotation_matrix_X and  
rotation_matrix_Y with the angles and multiplied:
rotated_normal = rotation_matrix_X * normal
rotated_normal = rotation_matrix_Y * rotated_normal

The result is (-30, -30, 59) which is far away from (-71, -19, 0).

What is the right way to compute the rotation parameters of the  
Transform filter out of the data of the Slice filter (Origin and  
Normal)?

Best Regards
Alexander