Sooo i was almost finished turning a hat that was originally part of a custom hairstyle into an accessory, but just as i went to check it out in Body Shop the texture was pitch black. I’m a bit confused since the preview of it actually looks somewhat right lol

Well, there's a bunch of little things that can go wrong, and/or needs adjusting with accessory files...
Can you upload the mesh and recolor package files?

Yup, here they are https://mega.nz/file/Pm43RaQJ#F9Miz...RYs49pyAzWovdxc

Accessories can act a bit "difficult" at times.

First of all, for the mesh file you either have to make sure you keep the "lens" group in the mesh file, or (properly) remove all traces of it in the mesh and recolor file (which can be a bit tricky), otherwise the accessory is going to flash blue ingame. You can use the placeholder OBJ from here: https://modthesims.info/t/283059 or make it yourself.
- Select a single polygon from the mesh and duplicate it, shrink it down with "vertex -> snap together", make sure it's assigned to the head, move it inside the area of the head, rename the group "lens", copy comments from the Frame group but change "name: lens" and "opacity: 0".

In the recolor file in the TXMTs, you can test out this setting for the ones that say "Frame" (don't worry about the "lens" ones):
stdMatAlphaTestEnabled: 1
(This enables simple alpha editing without transparency)

And in the "CMaterialDefinition" tab in the TXMT, make sure ALL the "Frame" Type lines say "SimStandardMaterial" and NOT "StandardMaterial"
(this fixes a material/texture issue that causes some weird lighting issues - it's a problem in most accessories directly cloned from ingame glasses, so you'll usually want to fix this every time you clone ingame glasses).

Maybe not an issue with your accessory in particular (since the texture is dark and not too visible, although if you notice it's too shiny or the wrong color it could be worth a try), but if you ever want an accessory to match the TXMT/material of most of the ingame clothes, these are the settings you can use:
stdMatDiffCoef: 1,1,1 (or 1,1,1,1)
stdMatSpecCoef: 0.099,0.099,0.099
stdMatSpecPower: 2

Thanks! That fixed the issue

Just so you know, that setting looks fine ingame on sims, but usually looks a bit odd in Bodyshop and CAS plus in thumbnails (in case you wonder).

If this bugs you, you can use
stdMatAlphaBlendMode: blend
stdMatAlphaTestEnabled: 0
(and when you import textures in SimPE, use DXT5)

but the "blend" setting has some annoying issues, especially if there are several layers to the mesh (transparency issues in hairs is one example), so unless the somewhat weird appearance in menus doesn't bug you, transparency and "cutouts" works fine for accessories through editing the alpha in Bodyshop or editing the texture in SimPE.

Omg i’m so sorry for not responding earlier, i did what you said and the accessory is now working! Thanks!