illustrating transparent tunnel while embodying solid front I'm trying to create a scene which consists of one huge block which is seen from really close such that no edges are visible. The inner life of the block should consist of various tunnels carved into the block whith connections to the outside (like a futuristic town). The block should be transparent to some point such that its inner life is visible, however it should be still obvious that there is a wall. 

For the block I used a glossy shader mixed with a diffuse one, then again mixed with a transparent shader. I added a plane as illumination from the side to get a reflection and an illumination gradient to highlight the wall but I'm not really happy with the result so far.

How do I make it clear that everything rests in a box with an obvious wall while still being able to show channels inside the material?
I think this is not a question of how to do it, but a question of what you want to do. My recommendation would be to think more about what you want to do, what you wish to communicate visually and how. Maybe look for something visually similar or attempt to sketch it. It is hard to achieve what you want if you do not know what you want. Work more on the concept so it is clearer.