First, congrats for the site. As for the Mac problem: In general, the Python APIs for Mac and Windows are identical, the major problem there is are path seperators. Make sure you never hard-code for : or as path separator but use os.path.split(). IIRC there's also a slight inconcistency in the TextureMapFileName() function: When called on a material with no texture, the Mac version returns a directory and the Windows version returns null. This also applies for the corresponding transparency/bump/reflection map functions.