Ok guys let’s see…
AO Is an Outdated Paradigm
Ambient Occlusion is a relic of an era when computational constraints dictated visual approximations over physical accuracy. It consumes resources by loading additional textures or calculating shadows where are not needed to produce results that contradict the physics of light.
Let’s consider two examples: a narrow crack in a surface and the entrance of a dark cave.
The Crack
When you look at a narrow crack from the outside, it might appear dark to your eyes. This doesn’t mean there’s no light inside the crack—it simply means that the photons inside are not bouncing back toward your eyes effectively. In reality, the crack is full of photons scattering in every direction, and with the right conditions (e.g., a direct light source shining into it), you would be able to see the interior.
However, AO maps don’t simulate this behavior. Instead, they artificially darken the crack based solely on geometry, independent of whether a light source is present or not. This is a direct contradiction to how light behaves in reality.
The Cave
Similarly, when you look into a dark cave from the outside, you might perceive the interior as pitch black. But in reality, the cave is not empty of photons. The photons from the environment enter the cave and scatter across its surfaces, though they might lose energy and fail to reach your eyes effectively. If you were to walk into the cave with a flashlight, you’d see the walls illuminated because the light interacts with the interior and reflects back to your eyes.
AO fails here as well. It “bakes in” darkness inside the cave regardless of whether a light source could realistically illuminate it. This approach ignores the dynamic behavior of light entirely, making it a poor representation of reality.
In short, AO creates “fake darkness”
that is computationally expensive and unnecessary in the context of physically accurate rendering. The transition to ray and path tracing, lumen … should eliminate these issues by accurately simulating light behavior, making AO an outdated and inefficient approach.
AO should—and will—be phased out in favor of more authentic methods.