Ambient Occlusion

Ambient occlusion (AO) is a shading technique that estimates how much ambient, indirect light reaches each point on a surface. Areas where geometry crowds together, like inside corners, crevices, and contact points, receive less light and are rendered darker. This produces soft contact shadows that make a 3D scene feel grounded and physically believable.

AO samples the geometry around each surface point to measure how much of the surrounding hemisphere is blocked by nearby geometry. The more a point is enclosed, the darker it becomes, independent of any specific light source. The result can be baked into a texture or computed live in a render engine.

Shadows are cast by specific light sources and move as those lights move. Ambient occlusion is a geometry-based effect that darkens areas where surfaces are close together regardless of any single light, approximating blocked indirect light. The two are complementary and usually used together.

An AO map is a grayscale texture that stores precomputed occlusion values across a model's surface. Baking it lets you apply realistic contact shading cheaply at render time instead of recomputing it every frame. It is a standard part of a PBR texture set.

Baked AO is precomputed into a texture from the model's fixed geometry and is very cheap to render but static. SSAO (Screen-Space Ambient Occlusion) is calculated in real time from the depth buffer, so it reacts to dynamic scenes but costs GPU time each frame. Games often combine both.

In Blender you bake AO by setting up a low-poly target with a UV layout, creating an image texture, and choosing the Ambient Occlusion bake type in the Render properties. For high-to-low workflows you cage the low-poly around a high-poly source so surface detail transfers into the map.

A baked AO map is extremely cheap to render since it is just a texture lookup. Real-time SSAO costs some GPU time but is far cheaper than fully simulating global illumination, which is why it is a popular approximation in games.

It is not strictly required, but AO greatly improves perceived realism by adding the subtle contact shadows the eye expects where surfaces meet. Without it, models can look like they float or feel flat. Most product and game pipelines treat it as a default layer.

Meshy generates PBR-ready 3D models with textures that respond correctly to ambient occlusion in any engine. That means AI-generated assets look grounded and detailed the moment you drop them into Unity, Unreal, or Blender, with no manual AO baking pass required.