I haven't messed with importing graphics into games/game engines yet, though I've downloaded that Platinum Arts Sandbox game & may try & do some things with that for my niece's & nephew to play on their computer, but will have to see...
last time I messed with a custom self made game/game engine package was almost 7-8 years ago when I bought some suite from Bestbuy/circuit city, that had a intro version of C++, & some game engine that was loosely based on Quake or Quake 2 if I remember right? was some sort of officially licensed yet sort of open source engine, I forget the name of the software package thing, but anyways, allowed you to make your own maps, & even edit aspects of the game engine to make your own custom made fps type games... also had the DirectX 6 SDK included with it too if I remember...
AND a Big Thick Book/Manual to read through LOL... of which I never really used...
but anyways, that was before I had even tried any 3D graphics programs & knew next to nothing of them, but knew I wanted to.
anyways, if the program/engine your using allows for importing of objects etc, its possible the format that you used to export either isn't the right format, or didn't export right...
some formats I know may be the "same" format, but might be different versions of it, & if the target program only uses certain versions, the exported object may not work right or show up right...
I have had similar problems with exporting some objects with certain Shaders/Textures I used or made in Carrara, only to find out after loading the object fine in something like Daz Studio (who make current versions of Carrara also), that the original Shaders or Textures don't render properly like they did in the original program...
I'm not certain, but I'm guessing in my case the shaders made in Carrara can't be rendered or supported properly in Daz Studio... & wondering if possible something similar could be the case in this situation... but looking at the object, as far as the textures go, I don't see anything thats really so advanced or unique (no offense or anything), that the game engine shouldn't be able to render it.
I'm wondering, if maybe the game engine requires the Textures seperate from the Object or Mesh, to be combined & rendered seperately in the game engine itself?
I know some models I have used in C6, the files I load sometimes combine the Mesh & the Textures as one file, others load up the Mesh with a basic texture & then require seperate Texture files to be loaded with it to get the end result...
wondering if maybe the same is required? a seperate Mesh file & a seperate Texture file to be loaded & rendered together in the game?
Wish I had more knowledge on this though, really do...