Shading flips / normal maps flip(?) when StaticMeshActor is rotated on the Z axis

Development Asset Creation
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1

Project on UE5, I am new to UE.
(Sorry if this is on the wrong topic, currently having trouble posting this.)

I have a StaticMeshActor with a material that has a base color texture and a normal map, but whenever the StaticMeshActor is rotated, something involving the material starts to flip, causing the model to progressively turn dark. I don’t know what the exact cause of the problem is but all of the arrows seem to point towards the normal map being the culprit.

This seems like it’s a very easy problem to solve and I’m just not seeing something, sorry if I am wasting someone’s time by asking about this.

If anyone has a possible solution to this problem, it would be greatly appreciated if you could point me in the right direction. If anyone needs any more info in order to help solve this problem, don’t hesitate to ask, thanks!

2

It kind of sounds like the material has lost the “Use Tangent Normal” and it’s treating it as a WorldSpace Normal…

3

could be worth checking your material if its using worldspace normal or something funky, Debugging using your buffer visualization window will help too, so you can double check if its your normals. double check your mesh normals in your 3d package too, sometimes funky business starts to happen there :smile:

4

Tysm! I didn’t know how to visualize normals before, tried it, and as I suspected, it is in fact flipping the normal:

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Changing it from worldspace sounds like it could be the solution, but do you know where I could check that?

5

In my material’s properties I could not find “Use Tangent Normal,” but I did find “Tangent Space Normal,” and turning it off seemed to work!
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TYSM for pointing me towards this! I most likely would have never seen this as it was tucked away under an easily unnoticeable Advanced tab.

1 Like
6

That’s the one. But when it’s unticked, that makes it WorldSpace (it doesn’t translate the tangent based normal (think local space) into WorldSpace at the end of blueprint). If it seems to be working it’s possible your normal map is in WorldSpace, but the rotation could well be wrong in the scene unless the material blueprint is rotating it somehow.