The realistic-ness came with a big button with the word "go" on it. Then a bunch of green grids jumped around my scene at high speed, gradually calculating photon bounces in front of my eyes, and when it was done, my whole scene looked realistic. It's called radiosity. It is good, but is kind of like baking your clay; you can't work with it more unless you want to get rid of the radiosity, and it's also static, so it can't change when the location of light emitters does. But there is radiosity rendering, although it lacks the adaptive subdivision that makes sure all the meshes have matching vertex resolution, since it's based on vertex colors.