i work with 4 viewports
i’v put a plane then remove two vertices to get a line
then N Key - set the angles at 45 degres x - y - z
i can see that in the side view and 3D the line is at 45 degres with de grid - so OK:D
but not in the top and front view :eek: 
ba da bing ba da boom :eek:
What the hec is happening there - how come it is not at 45 degrees with the grid :eek:
Tanks & Salutations:cool:
because that’s how rotations work
I think you want to rotate on only two axes, not all 3
Why not 3 ?
after all there are 3 axis!
if i put a cube at 0 0 0 and check it.
the line is definitly not at 45 degrees ?
the N key rot angles should be working normally but it is not this is more the center of my questionning !
how can i trust it now ?
i mean the value for the angles with this N-key
Salutations
If you have a line and its centre point is on the line, only 2 axis will be seen to rotate as the 3rd axis runs down its centre it will just rotate about itself.
If you rotate something one way when you rotate it again you get a componded angle, the 2nd rotation of 45 deg will only look like 45 if you view it square on from the first rotaion angle.
If you want a line at 45deg select opposite vertices in a cube a press F. Delete what you don’t want.