Occlusion & Lightmap

Occlusion & Lightmap exposes the standard AO and lightmap controls plus a bent-normal slot for proper indirect-specular direction. It grounds a Genesis material into baked lighting and gives crevices the contact-darkening that PBR needs to read.

When to use it

Every Lit material in a lightmapped scene.
Hero props where baked AO sells the contact shadows.
Indirect specular — bent normals bias the environment sample toward unoccluded directions.
Mobile baked-lighting workflows.

AO vs SSAO

Baked AO is per-pixel and free at runtime but locked to the bake. SSAO is runtime but resolution-limited. Stack them at 0.5–0.7 each rather than 1.0 to avoid double-darkening crevices.

How it works

The shader samples _OcclusionMap from the selected channel, scales by _OcclusionStrength, and multiplies into the diffuse and indirect terms. When a bent normal is provided, it replaces the geometric normal for the SH and reflection-probe samples only; direct lighting stays accurate.

Properties

Inspector label	Shader property	Type	Default	Description
Occlusion Map	_OcclusionMap	Texture2D	white	Greyscale AO texture.
AO Channel	_OcclusionChannel	Enum	G	Which channel holds AO. G is the Unity convention.
Strength	_OcclusionStrength	Float (0–1)	1.0	0 = no darkening, 1 = full.
Affects Direct	_OcclusionAffectsDirect	Float (0–1)	0.0	0 = indirect only (PBR-correct), 1 = direct too.
Bent Normal	_BentNormalMap	Texture2D	None	Optional bent normal for indirect direction.
Lightmap Influence	_LightmapInfluence	Float (0–2)	1.0	Scales the lightmap contribution.
Lightmap Tint	_LightmapTint	Color	RGB(1,1,1)	Tint applied to the baked lightmap.

Usage

Bake an AO map with the AO Baker tool, using a UV1 unwrap.
Pack AO into the G channel of a Metallic/AO/Smoothness texture (Unity convention).
Set the AO Channel to G and dial Strength to taste; 0.8 is the sweet spot.
For hero props, bake a bent normal in the same pass and assign it for cleaner indirect.


material.SetTexture("_OcclusionMap", aoTex);
material.SetFloat("_OcclusionStrength", 0.85f);
material.SetTexture("_BentNormalMap", bentNormal);

Tips & gotchas

AO multiplies indirect only by default, matching PBR convention. Raise Affects Direct only for stylized art.
Lightmap UVs (UV1) must be unique; overlapping UV1 produces bake artifacts.
Bent normals are tangent space — use the same import settings as a regular normal map.
AO is free when packed into an existing mask. Bent normals add one sample, usually worth it.

AO Baker — GPU-baked AO and bent normals.
Normal Mapping — the bent normal is the indirect cousin.
Shadows — receive-shadow path.
Texture Channel Packer — pack AO into MAS textures.