Alright ! So i did a veryy very veryyy dry video (no editing or anything ) of the process I did. Its very quick and not perfected but it explains what i mentioned above. I didnt sort the planes in milkshape - which you should do- but it did greatly reduce transperancy issues.
I didnt do the hat chops either - just the bare minimium ha, showing what i meant about changing inner planes to sim skin.
Since theres no editing ill explain what i did with timestamps here. Then after ill explain the work you need to do.
Sorry for the sort of rushed help ;-; I've just been very busy lately but I do want to help!
(And your not annoying hun! <3 Thats what we're here for) Heres the zip folder of the video plus everything I used in the video.
bloopFirst off I just started with importng the obj file you provided instead of exporting the LOD0 from your package - the LOD0 was very broken for some reason, it had backfaces missing and etc. So i just started from scratch.
0:00:00 - to 0:03:00 is just me eding the uv map to fit your texture - and checking the issues in milkshape.
0:03:00 to 0:05:00 is me copygn my Sylph Hair.package to Sims 4 studio --> Mods folder, then cloning my sylph hair (any swatch is fine i just chose first one)
I then export my LOD0 as LOD0Reference
I goto File Append and append the mesh (the hair mesh your working on from sims 3) into that .blend file I exported from my hair.
I change the GEOM Cut number to 0002. Because 0002 is the BASE hair without any hats.
0001 and 0000 are hat chops.
0003, 0004, and 0005, are the extra GEOMS I've added, however I don't rememeber which of the extra geoms I added are an extra geom for the base hair, And i don't cover hat chops in this video, so I just duplicate the base hair (GEOM 0002) twice, and put it as GEOM 0001 and 0000. (This will make it NOT compatble with hats, but this is just talking about fixing some transparency issues for now)
at approx 0:08:00 I duplicate the base mesh to make that sort of Underneath i was talking about - the part that will reduce issues - I delete the parts that will show the underneath sticking out. For example towards the ends. This is a very rough cutting off. I suggest to finnesse it a bit more beacause you'll see at the end some of the parts are still sticking out (But it gets its job done). By the way extra note - the hair needs to be fitted onto the sims head a bit more ^^ its a bit too floaty.
Then i scale it , and i change that extra geom to 0003, do weights and vertex painting (this vertex painting wont allow your mesh to move with the sliders but like I said quick method) and then I delete the old parts (my hair) . .
But oopsies! at 0:16:00 I made a mistake. I wasn't supposed to delete the old parts but replace them. So like I said above. I duplicate the regular hairr and label it as Geom 0000, 0001, and 0002, and the extra part underneath is Geom 0003, 0004, and 0005.
Then at 0:20:000 it imports correctly and I add your texture - then I change the base hair to sim glass in warehouse tab. And the extra part we made underneath to sim skin ^^.
My game take hella long to load (its because reshade mainly and my bleh processor)- so I just let it, and go make something to eat . . so skip to about 0:34:00!
As you can see a lot of the transperancy issues at the scalp are gone! There are still a lot left in other areas - but I didnt sort the planes.
Also the underneath is sticking out a bit - you see that skin colored bit i circle my mouse cursor around a little? Thats because
1) the hair mesh itself needs to be a bit more edited to fit the head more.
And 2) The underneath needs to be a bit more edited to stick out less.
So with a combination of sorting the planes in milkshape and adding that extra geom - transperancy issues can be greatly reduced - of course it takes a bit of work though and finessing to make it at least *near* perfection. (Nothings ever perfect of course!)
Go ahead and download creations from Stealthic Leah or etc. and export their LOD0s to blender. You'll see they use this same method (with the combonation of sorting planes) To reduce transparency issues. BUT - they still have very minor transparency issues *barely noticeable honestly*. This cant be 100% avoided it seems. Sims 4 wasn't mean to have alpha hair ~ we just have to make do ;-;.
I hope this helps!
Remember dont rush through like I did! I only rushed through to show you the jist of it.