How to bake an ambient occlusion (AO) map
An ambient occlusion map captures the soft contact shadows where a surface is partly enclosed — crevices, seams, and tight corners. Baking it from your mesh's geometry gives a PBR material grounded, believable shading and a base for driving dirt and wear.
The short answer
AO baking computes, for each point on your UVs, how much surrounding geometry blocks ambient light, and stores it as a grayscale map. Bake it from your model, plug it into your material's AO/occlusion slot (or pack it into an ORM map), and optionally use it to mask grime into recesses.
Step by step
- 1
Prepare your UVs
Your model needs a non-overlapping UV layout so each surface point maps to a unique spot in the texture. Overlapping UVs cause AO to bleed between parts.
- 2
Set the bake resolution
Choose an output size (1K, 2K, 4K) that matches your texture target. Higher resolution captures finer contact shadows but takes longer to bake.
- 3
Bake AO from the mesh
Run the AO bake. The tool casts rays from each surface point to measure how occluded it is, producing a grayscale map — dark in crevices, white on exposed faces.
- 4
Check for artifacts
Look for harsh seams, bleeding, or noise. If you see them, adjust the ray distance, increase samples, or add UV padding, then rebake.
- 5
Use the AO map
Plug it into the material's AO/occlusion input, or pack it into the red channel of an ORM map. You can also use it as a mask to confine dirt and grime to occluded areas.
AO vs cavity and curvature
AO captures broad, soft occlusion; a cavity map captures tight, fine recesses; curvature highlights edges. They're complementary, not interchangeable.
Many artists bake all three and use AO for grounded shading, curvature to drive edge wear, and cavity to settle fine dirt into seams.
Should AO go in the base color?
No — keep AO out of the base color map. Modern engines apply AO as its own channel, usually only to ambient/indirect light.
Baking AO into base color double-darkens crevices under direct light and is a classic source of muddy-looking materials.
Frequently asked questions
What is an ambient occlusion map for?
It adds the soft contact shadows in crevices and corners that direct lighting alone misses, grounding the surface and giving you a mask for dirt and wear.
Do I need UVs to bake AO?
Yes — AO bakes to a texture, so you need a non-overlapping UV layout. Triplanar painting doesn't need UVs, but baking does.
Why does my AO bake have seams or noise?
Usually too short a ray distance, too few samples, or not enough UV padding. Increase samples and padding and adjust ray distance, then rebake.
Can I bake AO in the browser?
Yes — Mixos bakes AO and curvature from your mesh in the browser, with no desktop baker required.
Bake AO and curvature from your mesh in the browser with Mixos — then drive realistic wear from them.