Model object receives odd lighting in-game

[Baelkin]

I've encountered a somewhat odd problem that I'm looking for some assistance with. For some reason, the lighting properties of one of the NiTriStrips objects on a game item is inverse of what it should be. As can be seen on the attached screenshots, it behaves exactly opposite of how it should when it comes to reflecting light from the game world - when the item faces a light source it becomes shaded and when it faces away from the light source, it becomes highlighted by the game world lighting.

 

First how it behaves with the light coming in directly from the front:

 

http://i425.photobucket.com/albums/pp337/Baelkin/ScreenShot60.jpg

 

http://i425.photobucket.com/albums/pp337/Baelkin/ScreenShot59.jpg

 

 

And this is how it behaves with the light coming in directly from the back:

 

http://i425.photobucket.com/albums/pp337/Baelkin/ScreenShot61.jpg

 

http://i425.photobucket.com/albums/pp337/Baelkin/ScreenShot58.jpg

 

 

And just to make sure it wasn't something unique to the subway environment lighting, I took one outside in the open in which the lighting also acts inversely on the object - the character is facing the "main" sky lightsource (direction established by looking at an environment object and facing the character to the heaviest shaded area):

 

http://i425.photobucket.com/albums/pp337/Baelkin/ScreenShot62.jpg

 

 

Sooo any suggestions as to what is wrong? I suspect I've messed up with the Normal map as the lighting worked fine using the "template" textures as both diffuse and normal maps.

 

EDIT: Bah, maybe not. Just tried removing the normal map from the texture set and the problem persists. Is there a way to "invert" the lighting properties of an object in Nifskope, making the current highlighted parts shaded and vice versa?

 

EDIT2: Meh, seems it's a mesh problem. Guess the only option left is messing around with the mesh and re-exporting it with the corrected normals. :pinch:

[Baelkin]

Apparently I screwed up some normals on the 3d model which caused the problem of the inverted shading. Specifically, if you in 3ds Max use the "Normal" modifier and apply "flip normals" your normals get... well... flipped and this shading error occurs. To fix the problem I used the normal options under the surface properties of the mesh object itself rather than using the unpredictable modifer.

 

I've also realized why this happened - sometimes, when applying the "Reset X-form" modifier prior to export, the normals mess up and the exterior shell polygons of the mesh become interior polygons and I used the "normals" modifier to fix the problem with the "flip normals" option tagged. I don't know if you can just skip the Reset X-form step, though considering it was the source of the problem, I think I'll mess around without on my next model.

 

Oh well... another lesson learned for the good of the community. :D

 

Model with fixed normals, applying the correct shader according to light source:

 

http://i425.photobucket.com/albums/pp337/Baelkin/ScreenShot63.jpg

[am0eba]

That was interesting being privvy to your inner dialog as you worked that out... Very informative images too.

 

Nice mask by the way!

 

_Dave_

[deliverance6]

nice gas mask kinda thing you've got there mate.

 

and yeh, i was just about to reply to have a look for flipped normals. glad you fixed it you'reself tho :)

ive had this problem a few times lol

[Baelkin]

That was interesting being privvy to your inner dialog as you worked that out... Very informative images too.

 

Nice mask by the way!

 

_Dave_

 

Haha, well I think it's nice to post the solution to the problem even though I found the solution on my own as other people might have the same problem, and would then be able to find this little "journal" using the search function of the forums. :D