How can I make the outside of a sphere transparent I want to make the outside of a sphere transparent so that when I'm looking at it, all I see is the inside of the opposite face. If I'm close enough to the sphere that I can only see a small section of the outside then I want to look through that section and see the majority of the inside of the sphere. To do this I just need to make it so the sphere is transparent when viewed from the outside but that the inside face is visible.
This can be done using the technique from my answer here, but with just a transparent shader for the "outside" material:



This setup makes the frontsides of faces invisible to camera rays and the backsides of faces invisible to non camera rays.