Is there an easy way to rotate normal maps in material editor ?
are you talking about 90° increments or gradual rotation? 90° could possibly be done somewhat fast, even though i’d recommend doing it in an image editor if at all possible. inbetween steps probably not as that is a fairly complicated calculation…
Gradual rotation.
I guess it will be complicated calculation.
I probably wont use expensive stuff but if anyone knows the answer, extra information is just no harm, right ?
I’ve came up with this material setup:
Make sure that the ‘RotationAngle’ matches the ‘Speed’ value of the rotator node but with the opposite sign.
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Yeah that wont work, because the way normal maps are made up of RGB (horizontal / vertical / depth) as soon as you start to rotate it, it changes the normal angle information.
Thanks mate, it seems to work flawlessly.
That value should be pi * 2, right ?
Notice how perspective stays same when rotation occurs and it seems cheap, I love UE4. 
nice one malkavian 
6 years later, time to make a relevant post
(just because it’s the first Thread I came across on my search)
You can do it easier and more stable this way:
Just use the same Rotator node and in the details panel, make sure that the second rotate node has it’s rotation center at [ 0.0 , 0.0 ] and plugin your rotation value multiplied by -1.0. Also the rotation speed of both Rotator nodes should be the same.
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Thank you!
You can use just TransformVector instead of second rotator.