Hi. I just updated my library version to alpha.28
It no more work to import in the scene an obj file which has mtl file.
Playground
https://www.babylonjs-playground.com/#95MJI8#8
Stable
https://www.babylonjs-playground.com/indexStable.html#95MJI8#8
Ping @brianzinn to see if he can check 
Does it work when you delete the MTL?
What program did you use to export it?
https://www.babylonjs-playground.com/#95MJI8#9
with mtl file, but not uploaded.
https://www.babylonjs-playground.com/#95MJI8#1
obj without mtl
I’m using 3ds Max to export
PM me the content of the MTL.
Here is
What happens when you delete the MTL reference from the OBJ file?
That really looks like something in the loader, since the MTL file is loaded in the network tab and additionally the onSuccess is triggered. Won’t be able to look at that until late this evening, but will report here findings as soon as I can.
Here is an obj without mtl reference and this is working
Kinda figured it would… hmm ok I have a really good idea what is going on. When I get more time to look into it Ill get you a solid solution.
It’s the format of your position vertices with an extra space. I will create a PR now to address. Thank-you for reporting.
merged!
Thank you all 