So everyone probably remembers how Mortimer Goth was supposed to have a widow's peak hairstyle like in the picture, but it was scrapped by Maxis.

Well, I found the mesh for the widow's peak from the game's files but right now I have no idea what to do.
I want to add them in the game but I have no idea how to do that and the countless tutorials didn't really help as well.

I found the mesh by opening Sims03.package (which is in EA GAMES\The Sims 2\Base\TSData\Res\Sims3D) in SimPE, and extracted tmHairPeak_tslocator_gmdc (which is the mesh) and it gave me three files:
- tmhairpeak.xml
- tmhairpeak.5gd
- tmhairpeak_tslocator_gmdc.obj

And right now, I have no idea what to do in order to get that scrapped hairstyle in the game. Help would be appreciated.

Technically the GMDC file isn't a mesh, its part of a mesh, you are still missing the other three pieces. There is no need for you to extract out those files either, just keep a copy of the GMDC and find the other 3 pieces. The other files would be found in Sims04, Sims05, and Sims06. You need a GMDC, GMND, CRES, and SHPE to create a mesh. You should also look in Sims07 and up for the TXTRs and LIFOs of that hairstyle. You should prolly reread some of those countless tutorials as well, cuz you don't even seem to have a basic grasp on hair meshing. Have you read mine yet? It's pretty wordy, but its because I tried to keep stuff simple while explaining a ton of stuff. Like the fact that tm is a teenage boy's hair. Have you looked at the GMDC in a 3D program yet? It might be a different one than what you think.

I'm also going to move you to Bodyshop Meshing, cuz that's what you are asking about. Lots of smart people over there too, I promise

(Where's simsbaby when you need him? He always made those hidden hairstyles usable)

Well, anything related to modelling has always given me a headache and eventually confused to the point of ragequit, but I'll have a look on your tutorial and countless others. Right now my SimPE seems to be flipping out after exporting the GMND and other stuff. (The mesh doesn't seem to have any textures. No wonder, it was scrapped anyway)

It's possible that the textures from another mesh will fit it. The hair in your Mortimer pic there looks similar to the "elvis" hair that did make it into the game, so I'd say it's worth a shot trying those textures once you get the mesh working. In fact you may be able to use that "elvis" hair as a starting point to build your new mesh from. You'll understand what I mean once you go through the tutorials.

Well, the mesh is in the game files so I see no point to go make a new mesh unless the mesh was corrupt or otherwise broken but if that was the case, I would just let it be anyway.
After all I'm here just to figure out how in heck do I make this hairstyle available in CAS.

Part of the process involves building a mesh package with an existing mesh as a starting point. You then swap the mesh and textures for your own. (Or in this case, for the scrapped Maxis mesh which you'll most likely have to edit.) I was suggesting that you try that "elvis" hair as a starting point (if it has the correct number of groups) and perhaps its texture will be good enough that you don't have to edit it much.

Okay, i guess i have to go download a modelling program then. In case I fail horribly, I better find someone who's taking requests.

The GMDC file which you found *isn't* a mesh. Its part of one. You need the other 3 pieces, that's what fansee is explaining. And I just went and looked, that mesh does have textures. They are in Sims07 like I mentioned in the first place. They are under umhairpeak. Considering they were able to take a screenshot of this hair mesh, it probably has all of its pieces. You will just have to link them all together. You don't need to do any meshing. This is a relatively easy task to do once you understand how a hair mesh and package goes together. Do some reading, learn yourself up, then give it a go!

Oh okay, better find a tutorial then and explore in SimPE tomorrow. I'll say if i run into any problems.

Still stuck on how to link the mesh and package together, or whatever I am supposed to do. I opened this mesh in SimPE (since the mesh for that hair is in the game files too) but found nothing that could help me. Nothing related to the mesh, just endless binary gobbledygook about textures and random things I don't even understand.

Then I found a few tutorials, got confused after the tutorial told me to make a mesh package which wasn't explained in a following link and still confused completely.

I don't even know how to make a package for the hair or if I'm even supposed to do that.

Why don't you try learning how to do a clothing mesh first. The are simplier and the tutorials are better. Do the 3 step unimesh tutorial exactly as the do and then see if hair meshing doesn't make more sense to you after .

Ooh, the tutorial seems cool and as you said, simple. I'll check it out tonight, right now I have to work on my 'hood.

http://imageshack.us/photo/my-images/138/whaty.png/

Alright, after fooling around with my recreation of my Sims 1 'hood recreation, I read the tutorial.
I made the mesh package, and next up, is linking the mesh. Which 3D ID Referencing File do I choose and link it to the mesh?

You might need all of them, depending on whether or not you've got multiple ages in the package. If you're just doing adult male, then you'll probably only need one of them. You need to find the 3IDR with the Instance number that matches the adult male TXTR with the same instance number (I think that's how it goes, anyway).

If you're linking all ages, then you have to match up each 3IDR.

(Maybe someone can refine that a little bit. It's been ages since I had to link hair meshes to recolours and I may have something wrong in that explanation.)

Okay, I don't have any idea why is this not working.
I linked the adult 3IDR to my mesh package, clicked other resource without committing changes like it says, then copying that package and the mesh package to downloads folder, testing ingame and it doesn't show the mesh I linked it to.
Am I supposed to do anything else after linking the 3DIR to the mesh package?

I can give the packages if someone feels like checking what did I do wrong.

Try it again, it takes a couple shots to learn something new.

Jeez, I've started over and linked 3 times now and it still doesn't show the mesh I linked it to.
Is there anything else I need to do than build the mesh package and link the 3DIRs to the mesh package?

Nope. That's it. But hair is tricky and you really have to pay attention because one wrong move and... it won't work. I don't even like to think about the hassle I went through for the two simple hair projects I did (two out of 195... that should tell you how much I enjoy fighting with hair meshes!).

Hm, well, I might try a few more times but if I fail, I'll probably go look for someone who can do it instead. Anyway, I felt like trying myself before doing a request.

Did you successfully do a clothing mesh first? You need to do that one first, its much simpler and you won't get the hang of hair if you don't.

Actually no, I thought it as pointless to make a clothing mesh because the hair mesh I wanted was in the game files anyway so I only used the tuttorial to learn linking and that other SimPE stuff. Eh, I'll try doing a clothing mesh later.

search with Simpe's finder for:
AmHairPeak and UmHairPeak
Extract the files and build a new package

The hair mesh is in the game, but its not linked and stuff, which is harder to do with hair than it is with clothes. Do the clothes first.

Blooms, OP doesn't know how to build a new package yet...

Wait what? When I almost had given up, I noticed that the mesh works, except it still has the base mesh's texture because I haven't changed it.

Good job! You are getting there!