Normal map issue : doesn't act as intended

Unity Engine
1

Hi ! After digging the internet for a day w/o any answer, I decided to submit the issue.

As it’s better illustrations then big speach, here we go :

First one is simply a diffuse with specular, everything ok

1219813--50189--$spec.PNG
1219813--50189--$spec.PNG1000×609 629 KB

And here’s the problem, when i add my normal map.

1219813--50191--$bumped spec.jpg
1219813--50191--$bumped spec.jpg1006×618 246 KB

Look at the red circle in the middle, there’s a big stone with shadow on the side (the light is on the right). As we look up to the next tile, we see that the side of the stone is suddently highlighted as if the light was on the left. See what i mean ? It’s like the normal map was acting reverse on the second tile …

The materials is the same for the 2 tiles. (Texture and normal map).

I uploaded the unitypackage containing this example : https://docs.google.com/file/d/0B871ZvKB4AC1MDdpejZwM19Nb2c/edit?usp=sharing

You can try it and move the light around to see the problem better. If someone can clarify that for me, I’ll be really thankfull.

1219813--50190--$bumped spec.PNG
1219813--50190--$bumped spec.PNG1006×618 761 KB

2

That was a tough one to spot - one mesh’s UVs (and so the normal map) are rotated by 90 degrees, the other mesh’s are not :slight_smile:

Hmm, but if I copy one object and turn it by 90° the seems appear also. I thought rotating the object shouldn’t matter given the texture is mapped identically…

3

Holy crap ! I though i had check that … It actually solve my problem … although I have a bunch of models that i need to swap the uvs … :frowning:

Drive me crazy getting stuck hours on things like that …

4

You’re right: this shouldn’t happen. Is your UV map mirrored?

5

Yeah that’s also my guess, especially as a rotation of 180 degrees looks correct again, so it seems to work in general. Funky thing though: The texture doesn’t look mirrored or flipped to me. Maybe I will investigate some time…