Quote -   You say that we can't add anything..... The scene needs an environment to render properly.....   ???????????????

An environement? The model provides the "Mad Scientist" lab, complete with table, books, rats etc. and it's enclosed inside a "room" (a cube). Thag should provide the whole environment. Unless I'm misreading you :)

The challenge for this is to work on lighting, camera, and materials. It should provide a lot of opportunities. 

Hope this helps.

Paolo

https://www.preta3d.com
FB: https://www.facebook.com/RealityPlugIn
Tw: @preta3d
G+: https://plus.google.com/106625816153304163119
The Reality Gallery: https://reality-plug-in.deviantart.com