Calculating the Infinite Focal Plane ("skydome")

"tomf" wrote:

In practice, beyond a moderate distance the brain stops using eye vergence to determine depth and instead falls back to parallax. So you move your head sideways and the relative motions of objects tells you the depth. You can easily move your head a lot more than the vergence baseline of 64mm, so this technique is useful at massive distances - it is fairly simple to tell the difference between an object at 1000m and one beyond it. Ideally most Rift games should at least use the "head-on-a-stick" neck model, which gives the player a significant amount of parallax.

Even beyond that, your brain will stop trying to "sense" depth directly, and simply infer it from context and domain knowledge. You don't only have parallax from your own motion, you also have the relative motion of distant objects, and your meat-brain's accumulated understanding about how the world works and thus how to interpret what it's seeing as depth. It's why we've had effective "depth" effects in video games via parallax motion back to the days of the NES, and why matte painted backdrops are so surprisingly effective.