Sorry if I missunderstud you, I thought you were asking about a joint rotation issue, which would most likly relate to a cr2 and joint paramiters, not a Wavefront Object. I can't help much with the code in your original post, I think the "vn" stands for vertex normal, and somhow defines a vector for the normal (the way light appears to be reflected from the surface). As to what the specific lines in your example mean I don't know, but the hash "#" symbol represents a comment line in obj files.