javascript – How to display a 3D object (*.stl file) using Django

I have a website developed using Django. Several 3D object files (*.stl files) are loaded from the administration. I would like to add the following two functionalities.

1- Being able to view 3D objects, both for an administrator and for a regular user.
2- In case of being a regular user, the object is only downloadable, under some conditions (for example if the user pay for the article.)

The following site is a good benchmark of what I want. sketchfab

I don’t even know how to proceed, any comment would be welcome.