I still have NO idea why the sins ships seem to have tangents that look like the very first picture while I thought your supposed to use the UV (of a special tangent map) which make them look like the second picture.

Im also wondering if there is any use for the vertex colour value in the .mesh file (unrelated but whatever).

I've got the above maps to a state im happy with, which is nice. Now I have to try and finish the rest of the script.

Slight feature creep - I try and do something, learn a better way to do it... realise what I could do with what I just learened - try to do it, learn a better way...

I can't see much else I want to do/can do now though, its cleaning it up and testing it to do mostly.

Well, it's not only a pitty for you max users. I'm using XSI for tangents, and have another winderful "bug"

I've made tangents for the sharlin for the b5 mod which look fine in XSI! Ingame the lightning looks awesome, but the light is coming from the wrong direction. with the star shining at the front of the sharlin, the light is rendered as if coming from the right (user perspective)

It could be normals, but to be honest I can't think of a way this could happen based on my own experience.  I've only had them flipped, which just turns the texturing/lighting inside out in-game.  You might check their directions to make sure each Normal is pointing in a direction perpindicular to the face of the polygon it's associated with.

I'm only just learning XSI tangent mapping myself (so no guarantees here), but you might try mirroring or flipping (is there a difference?) the entire tangent map on whichever axis is your front to back.  Just a near-random thought.

Oh?  That could be something I've had an issue with before but just not realized it.  When I work in max all I see are the normals that extend from each vertex.  What's the difference between what you refer to as the vertex normals and the triangle normal?

Edit:  After experimenting with it I see exactly what you mean.  I achieved the reverse lighting effect by selecting all normals and rotating them 180 degrees about any 1 of the axes. 

So, does the triangle normal just take each separate polygon and flip the Normals' orientation of all three axes?

@Aractain
I'm not sure that would help, since it is not exactly flipped but 90 degrees off. Thats what amazes me. It still looks wonderful, just not correct.

No, I did not modify the normals... I really have no idea how this happened. Haven't seen such a thing before. As for the workings of convertXSI, i think it just converts them and does not calculate, but I'm not sure.

Either way, the model still looks wonderful so I think for nor I have to live with the lightning being a bit off. Thanks for the input though.

I have just completed a model that I just could'nt get the tangent colors to match. No matter which way you orientate them some of the polygons don't have the the colors in them that others do, unless I made them all black. Which after many hours of almost completely fruitless research, I'm pretty sure your not supposed to do. They should be either green, blue or red. Now after hours and hours of trying to get my model all 1 color or close to it with gradual shifts in color, a flow on, so to speak. I just gave up in the end, I was just chasing my tail ending up back where I started, so finished off the model converted it put in the game and tried to pick the miss match's.

Well I might be getting a bit old but I can't see any anomilies. The only thing I could find was a bit of seam striaght up the middle which I'm pretty sure is a result of symtrizing.

here's the color map in softimage

Although my tangents are obviously not real good. I can't see anything that really wrecks the model. So I am sort of thinking that the polygon colors don't have to be that well matched. I could be wrong but I think its alright as long as you have red, green or blue in the apropriate places and even then it doesn't matter that much.

One thing I wish, as far as SoftImage is concerned, is that there was more info about it in the user guide, tutorials or anywhere. I can't seem to find anything that really explains what exactly is needed.

Edit; Oh! I forgot to mention. @TobyWahn_Kenobi, This is a long shot but could your lighting problem happen if you had your Aura & Above nulls about face / upside down?