Each model has a number of heads (some of them have 8 heads), arms, legs, bodies, hands, shields, weapons and accesories (bags, helmets...).
They can be equal in shape or different, for example 2 round shields, 2 oval shields and one pavise.
The game recognize which object to pick because of some comments. In fact you can say that the game picks or not randomly an object, for example a helmet. In such case some men will carry helmet and others will have the head uncovered. And the game will pick only one element with the same "comment" about the type. For example all the heads have the comment "head" and the game will take only one of those elements.
The texture is a big file with the different elements in the same number. For example if the model has 3 bodies, in the texture file the three different bodies appear, and each mesh has a different uvw map, that is, each mesh is linked to a different part of the texture file.
All the elements are divided in two categories: figure and attachments. It is possible to assign a different texture file for each category, and in fact M2TW does in that way. All the textures for weapons and shields are in one single texture file, that is shared by several units (or even all the units of the same faction, I'm not sure).
I don't know if it is clear enough.

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