hopefully, this is a simple noob issue. Yes I have seen that it's been asked again and again and again, and I have tried lots of the solutions but I'm still stuck. 

I have a model that I have applied a texture to and it renders nicely in Blender.

[![Blender screenshot][1]][1]

Ideally I want to export this to Shapeways for printing in colour sandstone, or when I eventually get an Mcor Arke, print it on there. So, I have a few options, DAE and X3D for example, these require the texture to be alongside the file in a zip file, and when I upload them, Shapeways says there is a texture (probably because the zip file included a PNG file), but won't render it. When I look in the X3D or DAE file with a text editor, there is no reference I can find to the PNG texture file.

I also tried [this post][2] on using the blender render engine, but it still doesn't have a reference to the texture when I export the object.

From when I used to do scanning, PLY seems to have all the image data in the file, so I tried that. Interestingly, Paint 3D recognizes PLY files and renders my bust scan... but, still no model of mine. I thought it may be the mirror modifier, but checking the export attributes, it applies those and includes the UV data, and I applied it manually to test anyway, but no.

[![PLY export panel][3]][3]

Stumped, I continued my search. There was [this post][4] about not using nodes, but as I walked through the screenshots, I didn't have the "Mapping" tab that was there, then I did something somewhere and it was there, but it didn't have a UV option for coordinates, when I did the original unwrap I did use the smart option... because I followed a youtube example, so I went back to the beginning of this article, and did the unwrap.... but now I cannot see the material rendered at all in any view. I can't seem to find a walkthrough example of a complex paint job without nodes.

Finally, I found [this post][5]. I didn't really understand the explanation, but it did mention baking, which I saw in an option somewhere. So I gave that a pop.

[![bake mode][6]][6]

Still nothing. So now I'm out of ideas. Any other ideas much appreciated, but, please bear in mind I still don't know Blender all that well.

If you're interested, [here is a zip file][7] with my .blend file and texture.

Any help much appreciated before I lose my mind.

  [1]: https://i.sstatic.net/RsGmt.png
  [2]: https://blender.stackexchange.com/questions/19115/x3d-not-including-textures-in-file
  [3]: https://i.sstatic.net/tQ4bK.png
  [4]: https://blender.stackexchange.com/questions/42246/textures-not-showing-after-collada-export
  [5]: https://blender.stackexchange.com/questions/57531/fbx-export-why-there-are-no-materials-or-textures
  [6]: https://i.sstatic.net/2SMZN.png
  [7]: https://www.dropbox.com/s/98ixzsohjgf2d0e/hollow%20rhino%20and%20texture.zip?dl=0