When glass on a building (or any mirror) is perfectly perpendicular to the ground, the perspective of horiizon reflections is the same as if the building wasn't there and you were looking at the horizon directly. A little bit of trigonometry verifies this, if you're of a mind.

So - with the camera floating a couple hundred feet off the ground, as in my first render, the horizon passes through the middle of the buildings. Maybe this is an unfamiliar viewpoint, but it is pretty much correct. There is some small amount of distortion due to the fact that the environment sphere is only 750 feet across, not 40 miles, but this only shifts the results a few degrees.

Anyway - the point I was making was you can do an 8 minute IDL render and have it come out pretty nice. The particular reflections of scenery aren't the point - the point is that the lighting from sky and ground is very well taken into account with no fussing, guessing, and test rendering using IBL + AO. I didn't do anything to tweak the lighting - with IDL it is completely automatic.

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)