I have a 3d file in .fbx format, but I can't see the selection option as per the attached image? And what is the config.jason file for and how can I create it?
You need to create config.json manually with some paramaters like: Folder name (id), Product Title (name)..
"name": "Sols imperial",
As mentioned earlier you need to CREATE manually that document. I couldn't find any builders. Just use Notepad or something like that. Best way is to buy prepared 3D model. We did that now our 3D designers figuring out how it was created and testing params..
I'm not 3D designer & I'm not FPD developer. Just sharing what I know, and looking for help also.