Xnormal artifacts on an airplane model

VonDoom

Hey guys, I am baking some lines and panels onto an airplane model, but I have hit the wall. When i re-import my normal map into max, i get these errors as if the normals are flipped or something.

I use the default settings in the max exporter and dont use an external cage file, + "average normals" in the options of the high definition mesh in Xnormal (or the map turns red and orange) The lowpoly has ONE smoothing group btw.

Below is the exploded high and low poly mesh



Any help is much appreciated !

Synaesthesia

That's because the normals are flipped, at least as far as Max is concerned. Max expects Y- - just invert the green channel in Photoshop and you're good to go.

Alternatively, you can flip the green channel in Max's normal bump node as well.

On a side note, I'd highly suggest straightening out your UV shells. You'll get a lot of aliasing on your panels using slanted UV islands.

Scruples

It actually looks like this is either the gamma issue or it's being applied as world space normals, my money is on gamma.

Try disabling Gamma/Lut correction in rendering>Gamma/Lut setup.
iirc you'll have to re-import the normal map after disabling.

Method in normal bump node should be set to Tangent (it's the default so I don't think this is the problem)


People have also had trouble with .png and .tga files importing their own gamma profiles into Max, not sure what causes that as it never happened to me, so you can try a .bmp if the issue remains.

VonDoom

Thanks for the replies, @Sctuples I reversed the green channel and used a bmp file, but it just inverted the bad shading, it still looks about the same : ( Btw when you bake in Xnormal, you set the smooth normal option to "average normals" in the dropdown box of the high and low def meshes, right?  Nevermind, gamma was set to 2.2, i set it to 1 and seems like either that or using a BMP fixed it. Maybe normal maps have issues with the alpha channel.

@Synaesthesia Do you have an example of what you mean with straightening uvw shells ? I take it its not the same as pelt/relaxing uvws.

huffer

It means your UV's (and UV borders especially) should be horizontal or vertical, not at an angle, so as not to induce any visible artifacts (think of the difference between a straight line made of 10 pixels and an angled line made of 10 pixels..it will look like a stair).

VonDoom

@huffer Something like this?