We’ve upgraded our support for 3D Models, you can now use multi-textured files. FBX files now support embedded textures in AR, no need anymore to upload texture files separately. OBJ files now support bundled .zip with support of .mtl files and multiple textures in AR as well.
You’ll notice that the 3D Models upload panel changed a bit, and that you don’t need to change between “Web/Web & AR” usage, simply choose whether to upload a FBX or an OBJ file. The documentation has also been updated, have a look here for more details.