I've been working on trying to add some hair models to replace the ones in game that I don't like very much. I've managed to copy in the NiTriShapeData blocks and get everything how I want it to look in the nif file. I've even saved the files and opened them again with no errors. However when I start up fallout 3 and try to load the new hair files in the game, the game crashes instead of displaying it. I'm not sure what I'm doing wrong as I've followed all the guides I've seen to the best of my ability. I'd really like to be able to import some models and lend my texturing skills to this game. But these nif files are really difficult. Any advice or help?