Normal maps from blender are rendering incorrectly!

Development Rendering
1

I am creating a character model in blender. I sculpted a high polygon model, and then i baked normal from the high poly mesh to a lower poly mesh. In blender, i have no problem with seams, the bake works seamlessly, but when i import the model in UE4, i get this huge seam problem that i cannot figure out how to fix. It looks like UE4 is rendering the normal map differently than blender does. I use tangent space normal, but for some reason in unreal, the normal map flips at the backside of my character. I have two images to demonstrate the problem (WARNING: HUGE)

In Blender (no seams, normal map is rendering the sculpted information)

Normalongelma1.jpg
Normalongelma1.jpg1920Ă—1200 371 KB

After exporting to UE4:

Normalongelma2.jpg
Normalongelma2.jpg1920Ă—1200 677 KB

Anyone who knows whats going on here, help would be really appreciated!

2

Try to flip the green channel -> double click on the normal map - search for “green” - flip it :slight_smile:

1 Like
3

I multiplied the normal map with a constant 3 vector with values of 1, -1, 1. And it works thank you!!

Could you explain me whats going on with the green channel?

4

The values in the green channel of your normal map control the up/down vectors. When it’s wrong, light appears to be hitting the mesh from the wrong direction. When you flip it, you reverse that lighting vector information, and everything looks right :smiley:

5

Okay now it makes sense, thanks for the info!

6

Are the compression settings of the textures correct?

7

you don’t need to fix green channel in material editor you can flip it in texture properties