Ambient occlusion maps in PBR add soft contact shadow in crevices. They are useful, and they are also the fastest way to make a physically based material look pre-baked. AO is not part of the metalness-roughness core. Treat it as a directional, optional layer you can fade—not as a fourth required map.

What ambient occlusion represents

AO answers a simple question: how much of the hemisphere around a point is blocked by nearby geometry or by height in the texture. Tight mortar, fabric folds, and panel gaps receive less ambient light, so they read darker. A good AO map is greyscale, high contrast in cavities, and almost white on open flats. It should not contain colored dirt or a key-light direction. If it does, you are looking at a lit photo, not occlusion. Load it as non-color / linear data, same as roughness. Map roles are covered in what PBR textures are.

Baked AO versus real-time AO

Texture AO is baked from a high-poly mesh or from a height map. It travels with the material and works even on a flat plane, which is why tiled wall and stone packs on Locker3d often include it for mortar depth. Screen-space or ray-traced AO is computed at render time from actual mesh intersections. Offline path tracers already darken corners through GI. Stacking baked AO on top of Cycles or Corona GI is how you get black grout that never lifts when you add a fill light.

How to combine AO with albedo

The common node is a multiply: albedo × AO, then into Base Color. Keep the mix soft. A 0.3–0.6 factor is often enough; a full multiply can crush midtones. In Unreal, the ambient occlusion slot on a lit material is meant for this data—prefer that over multiplying into base color when you also use GI. In Blender, multiply only if the shot needs extra cavity and you are not already using heavy AO in the render settings.

  • Use texture AO to sell detail on tiled planes (floors, walls, terrain).
  • Skip or fade it on unique meshes that already have baked mesh AO or strong GI.
  • Never put AO into roughness or metalness unless you are building a dirt mask on purpose.

When to skip AO entirely

Skip it for product shots on a clean studio HDRI, for metals you want to keep bright in the gaps, and for any real-time budget where you already run SSAO. Skip it when the albedo is already a little dark in cavities—you would be double-dipping. Beginners often add every map in the zip; that is how a nice concrete slab turns into a cave. PBR textures for beginners lists AO as optional for a reason.

Color space and intensity control

Non-color on the image node. If AO looks milky, the file was probably saved with sRGB gamma. Invert only if the pack shipped a cavity-white-on-black map and your multiply expects the opposite. After that, control look with a gamma, color ramp, or mix factor—not by baking a harder AO. Soft AO reads as wear; hard AO reads as a stamp.

Using AO as a dirt or cavity mask

The more useful PBR trick is to treat AO as a mask, not as shadow. Multiply a dust albedo only in dark AO pixels. Raise roughness in cavities so grout is more matte than the tile face. That keeps lighting physical while still telling a story. Locker3d CC0 textures sometimes include AO you can reuse this way in commercial work; see what CC0 allows. Wiring extras in Blender: how to apply PBR textures in Blender. More notes: blog.

Frequently asked questions

Do I need an AO map for a correct PBR material?

No. Albedo, roughness, and normal are the core. AO is extra contact shadow. Path tracers already compute occlusion from geometry; extra AO can double-darken corners if you also multiply it into albedo.

Should I bake AO into the albedo texture?

Avoid it for reusable PBR. Baked AO cannot relight. Keep AO as a separate map or a cavity mask so you can fade it, use it only in a dirt layer, or disable it in offline renders.

Do Locker3d packs include ambient occlusion?

Some Locker3d CC0 sets include an AO or cavity map alongside albedo, roughness, and normal. Use it as a multiply or mask, in non-color space, and keep intensity modest.