Warning: There are two kinds of uv texture coordinates in Blender: per vertex ("sticky") and per face vertex (uv in NMFace). In the first, there's only one uv pair of coordinates for each vertex in the mesh. In the second, for each face it belongs to, a vertex can have different uv coordinates. This makes the per face option more flexible, since two adjacent faces won't have to be mapped to a continuous region in an image: each face can be independently mapped to any part of its texture.