I have created a obj file using python and included vertices(v), texture coordinates(vt), triangle normals(vn), and triangles(f) in that order. The mesh loads correctly in all the software I have tried (Blender, Unity, etc), however the UV map always fails to load so the texture coordinates must be incorrect, but the format seems to correctly follow what's specified in documentation: https://en.wikipedia.org/wiki/Wavefront_.obj_file
Example of each element of the obj file:
v 104.0 29.0 58.0
vt 0.659 0.263
vn -0.7071067811865475 0.0 0.7071067811865475
f 7508 7763 7764
Where all (vt) values fall between 0.0 and 1.0 (inclusive)
The file imported to blender with no UV map shown
When a textured material is applied the mesh it adopts a monochrome colour which I presume to be how different software manage no UV map.
I cannot work out why the UV map isn't importing correctly as the .obj file seems to be made correctly, so I would really appreciate any suggestions.