Hi Granada,
I try the importer i GG itself. I can import the model and save it as .dbo and .fpe... but no painting or texture is recognized by GG.
Asset Forge did export the textures. But GG don't care. While Unity3D is importing with textures.
In Asset Forge I can export as OBJ, FBX, DAE, GLTF and STL. I can choose export with or without textures, the Orientation and the Scale.
The Model exports great but all is grey.
In the Windows10 3D Viewer App, I see everything fine. Even the textures. Just GG is ignoring them.
I attached a little FBX file at this post, for testing.