What are the parts of a skin?

[albmont]

I don't quite understand this "mesh" thing (I am an old computer user who don't trust a code that I can't read, hack and understand), so can someone please enlightnen me?

When I open something that was created using this mesh with BodyShop, I get six files:

body_alpha~stdMatBaseTextureName_alpha.bmp
body_alpha~stdMatBaseTextureName.bmp
body_alpha~stdMatNormalMapTextureName.bmp
body~stdMatBaseTextureName_alpha.bmp
body~stdMatBaseTextureName.bmp
body~stdMatNormalMapTextureName.bmp

I don't even dare to think about the MapTexture files, but I have played before with *alpha.bmp and *TextureName.bmp - and there are two sets of them.

What is their function? Does it mean that we can have two layers of clothes? If I make the outer layer totally invisible (by setting the body_alpha~stdMatBaseTextureName_alpha.bmp to black) will I have only the effect of the inner layer?

[BeosBoxBoy]

um - yes - the whole point of the name for the mesh is to convey that fact.  Alpha layer ergo Alpha skirt.

As for their fuction this is not the place to ask for mesh and recolouring help.

See this excellent explanation: What is a mesh?

I am splitting this topic and moving this portion to Mesh Creation & Recoloring Help
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A composite 3D model or "alpha mesh" is comprised of 2 or more parts

It is import that you understand not all composite 3D models in the Sims 2
work the same way.  Some have a completely different purpose that the
answer I am giving, but rather than confuse you and myself with an over
complicated explanation, I will address only Marvine's mesh.

body_alpha~stdMatBaseTextureName.bmp
body_alpha~stdMatBaseTextureName_alpha.bmp
body_alpha~stdMatNormalMapTextureName.bmp

As you can probably guess from the name, body_alpha is the "outer layer."

body_alpha~stdMatBaseTextureName.bmp
body~stdMatBaseTextureName_alpha.bmp
body~stdMatNormalMapTextureName.bmp

As you can probably guess from the name, body is the "inner layer."

the items having ~stdMatBaseTextureName are the "texture"
which you should remember from the What is a mesh? topic.

the items having ~stdMatBaseTextureName_alpha are "masking
layers" - in short - this is the determined invsisible area.

the items having ~stdMatNormalMapTextureName are a "normal map"
or -- to use the common error of the Sims community in naming it --
the "bump map."

I will address now only the normal map - since you seem to have a grasp of
the purpose of the other two sorts.  The normal map is a sort of reflectivity
height map, it can emulate minute changes in the surface of the 3d model.

It only emulates these detail by altering the way light "reflects" off the
surface of the model.  A true bump map would cause variations in the
actual surface.  if you look at any Maxis skin with a normal map you can
get a general idea of what is and isn't important to a normal map for
the Sims 2 skins.