I have this OBJ file with only vertexes (v) and faces(f). Is it possible to calculate the Texture vertexes(vt)? I need a UV-map and I guess that is what the texture coordinates are representing?
In general creating the texture coordinates is part of an artists work when creating the model, so for many objects the texture coordinates are created in a 3d model editor (Blender, 3ds Max, Maya, …).
For some objects it is possible to get reasonable texture coordinates by projecting the points onto an enclosing simple object (sphere, cylinder, …) and use the parametric coordinates (which are 2D) of the projected points as texture coordinates.