Yea and you will probably have to do it again each time you make a new hat object.
That's so strange. Anyone know what the reason is? just curious.
[EDIT:] After having the same problem even after using this solution, I put "Update FaceGen Model Availability" into Google and found this!
http://www.fallout3nexus.com/articles/article.php?id=134Apparently for these sort of items the game needs a little more data to understand how the .nif is supposed to be used. There are a couple things that are left out of the tutorial, but it's easy to figure out. #1. Not only do you need the HeadHuman.tri, but you need the HeadHuman.egm too or you will get an error. #2. Afterward you can delete the extra files. The only two you need are the .NIF and the .EGM. The .OBJ, and the .MTL can be deleted.
Works like a charm now, and it's permanent! :celebration: