I have a custom torus-based environment I imported from a Collada file (created in Blender) that whenever it is viewed from the inside, appears transparent from any camera perspective, regardless of if a game is running or from the editor.
I'm not clear on what the cause is here with this mesh -- at first I made sure it wouldn't occur again with I "Triangulate" the mesh, to the same results. The same behavior exhibits itself when I import from an OBJ file (seen in the distance on the first photo).
I'm sure that i'm missing a step in the process, any ideas on what I can do to remedy it?
The original Blend file and DAE/OBJs can be viewed/downloaded here.