See here:

http://s1172.photobucket.com/albums/r567/ooofbaer/

As you can see, the way light interacts with the feathers is problematic. Light hits the under side of the feathers, but never the surface. Basically, the surface is in shadow when it's supposed to be in light, and the under side is lit when it should be in shadow; and vice versa.

The effect is nice, but I'd also like to be able to see what the feathers look like when the sun or another light hits the surface, as I should do.

How do I fix this?

Have you tried (In nifskope), clicking the feather's mesh in the 3d window, right clicking and messing with the options there?

(Flip normals, face normals, update tangent space may potentially fix the problem - basiclly your normals are out of whack)

I don't know anything about meshing. This will be difficult...

What do I need? Blender/Maya and Nifskope. Anything else? Does someone have a link that points me to a tut on exactly how to fiddle with the properties I'm trying to fiddle with?

Just NifSkope should suffice for this. To expand a little on what Ryujiin said:
right click on the TriShape that contains the feathers and:
Mesh>Face Normals
Mesh>Update Tangent Space

Should fix things right up.

Okay. Thanks, throttlekitty and Ryujiin.

Will this remove the under-lighting? It looks kind of nifty (if too bright), so I'd like to incorporate it somehow. Feathers do do that IRL, just not to the extent that the fault here does it.

It worked!

It didn't work.

Maybe I'm doing something wrong... Try again.

I'm in way over my head here.

I open the _0.nif file. I click on 0 NiNode. I click on 42 NiTriShape (the armour). Then I right click on the armour in the rendering screen and select "Face Normals" and then "Update Tangent Space". Then I Save As the file and move it the appropriate Data\ directory.

I repeat this for the _1.nif.

It doesn't solve the problem... Am I doing something wrong?

Edit: I feel like I'm corresponding with myself. If you could all help me figure this out... that would be great.

Click on the feather in the render window so that it's triangles are highlighted and the proper Nitrishape will be highlighted in the data list. That's the one you want to alter.

That's not working for me. Wherever I click on the armour, the program highlights 42 Nitrishape ForswornArmorF[35]... ? It won't highlight any specific section of the armour for me.

If anyone wants to help me figure out what the problem is, you're more than welcome to DL the modded files. Links http://forums.nexusmods.com/index.php?/topic/543848-how-lighting-interacts-with-this-armour-arggh-help/page__view__findpost__p__4423859.

(Problem's been solved. No need to have these up, anymore. All files have been deleted.)

I'd be overjoyed if someone wants to fix the problem for me and just let me DL the fix. I can't really progress any further on the female Forsworn armour until I sort that shadow. The feathers and necklace are pretty much the only things left to do, apart from a few touch-ups here and there.

http://forums.nexusmods.com/index.php?/topic/543848-how-lighting-interacts-with-this-armour-arggh-help/page__view__findpost__p__4424135

Test your specular settings... If you turn-down specular distance to zero... does it go away? If so... the following may be your issue... (May still be the issue if that does not change anything, because specular-range may only be for the "world" setting, not the self-specular setting.)

You have "Specular" as a solid color of "white"... ? (In daylight, it looks fine because everything-else is lit-up by ambient-light, in shade it looks fine with no light because it is not being highlighted, but near a light-source, the whiteness tells it to reflect the light or "Glow". If you don't have a specular-map, it may just assume you want it white/grey...)

If that is the case... You want pure-grey, to show only mild brightness, or pure black, which should make it non-reflective but it may turn it black in daylight. (If it turns black, use grey 127,127,127 as RGB values.)

Same if you have "Use vertex colors", and you didn't burn colors onto the actual vertexes, the default may be white... Thus, overly bright unless you grey or black the vertexes, or uncheck "use vertex colors".

If not specular, then it is failure of "calculated normals"... Flipping them may work, but it may not... (Normals are the quick-angle face of the vertex faces. Normally you want them facing OUT, and the IN faces should be OFF or invisible, not double-sided... that is just wasting rendering of the unseen side. Used for trees, feathers, clothing, but not normally armor...)

You should be able to "Check normals" which will show them as protruding lines from the center of every vertex, or as one of two specified colors. (Unless you know which color is IN and which is OUT, the color indicators are useless. Even more useless when certain exporters flip-normals when they calculate them backwards.)

No, the problem was actually with http://forums.nexusmods.com/index.php?/topic/543848-how-lighting-interacts-with-this-armour-arggh-help/page__view__findpost__p__4424135.

Thanks for posting, anyway. Normally I just fiddle with CrazyBump until I get a vague approximation of what I want for the specular. I was putting them off until the very end, by which time I planned to have read up on how to do it. Now I know what to do and to look out for, and you've saved me some hours.

Edit: My brain is slush -- I stayed up all night to figure out what was wrong with this armour -- so I'll digest this when I wake up. I'm going to sleep now. I'm a bit confused as to what you're referring -- speculars, meshes, normals? (It seems like a mix... ) Vertices are for the meshes, correct?

Maybe this'll make more sense when I wake up. Thanks again for the comprehensive troubleshoot.

I don't really understand any of this. What is "use vertex colours", "calculated normals" and "check normals"? Could somebody explain this? It doesn't have anything to do with the problem in the OP, but I'd like to learn about this anyway, as I might run into a problem somewhere down the line to which one of these is the answer.

Anyone? Can anyone explain what any of the above means?

"vertex colors" are a data element that can go in a nif file. If present, each vertex (each corner of a triangle) will have a color that can be used when rendering that mesh.

"normals" are also a data element that can go in a nif file (or in a normal map). "normal" means roughly the same thing as "perpendicular" and it's a special bit of data that the game uses to calculate how light makes an object look. (Basically, it's a pointer in some direction and if the normals are in the nif file you get one normal for each vertex, where if you use a normal map you get one normal for each pixel in the image.) I am unclear on how the game chooses between using vertex normals or normal maps, maybe someone else can explain that part.

"check" is a verb -- it's something for you to do.

"calculated normals" is the result of something you might do using nifskope (or perhaps using other mesh editing tools). This means that you ask the software to run a calculation that calculates a new set of normals based on the geometry of your triangles. This is often "close enough to what you want" to look good in game.

Thanks for that.