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Normal map changing the global orientation of the specular.

ng.aniki
polycounter lvl 13
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ng.aniki polycounter lvl 13
Hi !

I came up on this problem everytimes lately, maybe because I changed a little bit my pipeline to create normal maps. maybe I had this everytimes without really noticing it ?

Here it is:

(I am doin that in UDK, but I guess it would do the same with any game engine/renderer.)

When I apply one of my normal map in my material, it completely change the orientation of the specular light.

Here is a screenshot:

6a8c04148c5a6b757ffcc8471198a.jpg
>The light did not move, but the specular seems to be coming from somewhere else.

And now, with this normal map, the specular on my mesh will not fit with the lights in my scene. I guess it is happening because there is some kind of offset, but I do not understand where it is coming from.

I first generate normal maps from textures and handpainted heightmaps with Crazybump, and then I combine them with nDo ('Overlay Normal' script) in Photoshop.


-Could someone explain me why this is happening ?
-And how could I fix this ? Darken or lighten red and green channels of my normal map to cancel the offset ? Or, maybe I am doing something wrong in my pipeline..

-An other question, about something different, but leading to the same kind of problems:
I read that, to make the normal map more powerfull, we have to multiply Red and green channels by whatever we want. I tried that in UDK, it works, the normal map appears more intense, but the orientation of the specular is not the same. Am I missing something ? Or it is linked to the first problem ?

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