Baked Lighting and AO for VR: Setup and Optimization

Realtime global illumination in mobile VR is a dream that shatters against 6.9 ms per frame. On Quest 3, neither Lumen nor decent-quality SSAO is possible without drops. We offer the only way to get rich lighting with complex shadows and contact AO — bake it in advance. Our team has 10+ years of VR development experience and has completed over 50 projects for Quest and PC VR.

But baked lighting in VR comes with its own set of problems not present on flat screens. Let's break down each one.

How to avoid UV seams in VR?

The first headache is seam stitching. With default settings, the edges of adjacent UV islands on the lightmap produce dark or bright lines at mesh seams. In a regular game, this is masked by a moving camera. In VR, a stationary player examines a room corner up close and sees every artifact.

Solution: in Unity, enable Stitch Seams in Lightmap Parameters settings, reduce texel size to 0.1–0.2 for static environment meshes, and ensure UV2 (Lightmap UV) has sufficient padding — at least 2 pixels for a 512 atlas, 4+ pixels for 1024 and above.

Why does temporal flickering occur specifically in VR?

If the lightmap contains gradients with high-frequency details (sharp shadows from small objects), Asynchronous TimeWarp picks up the old frame and interpolates — a slight shimmer appears on static surfaces. This is solved by smoothing the AO radius and disabling sharp point shadows during baking.

Stereo mismatch is another feature. In VR, two eyes see the scene from slightly different angles. Baked specular highlights are baked for a single viewpoint and do not change with head movement, breaking depth perception. For mobile VR, it's better not to bake specular at all — only diffuse + AO.

How to properly set up baking for a VR scene?

Choosing a baking backend. In Unity, Progressive Lightmapper is standard. GPU Progressive (via OIDN denoiser) is faster but requires tuning: increase Sample Count to 512–1024 for gutter zones, enable Prioritize View for areas visible from typical player positions.

Splitting into Baked and Realtime. Not every environment needs to be baked. Static walls, floors, ceilings, large furniture — into Baked. Objects that may move or react to the player — into Mixed or fully Dynamic with Light Probes. Light Probe Groups are placed where dynamic objects appear: interaction zones, NPC paths.

Ambient Occlusion. In the baked version, AO is part of Indirect Lighting or a separate map from Substance Painter/Marmoset. For VR, we recommend contact AO with a small radius (0.05–0.15 m) and high intensity: it gives objects a sense of weight without distance artifacts. A large AO radius in a VR room creates an illusion of "dirt" on walls. More about Ambient occlusion can be found in the encyclopedia.

For Quest: lightmap atlas maximum 1024×1024, ideally 512×512 for most scenes. Multiple atlases are better than one giant — this simplifies streaming when transitioning between zones. Storage format: ASTC 6×6 via override in Texture Importer.

What is included in the work?

Baking setup is performed turnkey and includes:

• Audit of the current scene: check UV, lightmap atlas, batching.
• Choice of backend and baking parameters (Sample Count, denoiser, padding).
• Placement of Light Probe Groups for dynamic objects.
• Creation of baked maps (diffuse, AO) and compression for the target platform.
• Performance test: check FPS budget (<8 ms per frame for Quest).
• Handover of the project with comments and recommendations for further support.

Our clients save an average of 30% of time on manual lighting optimization, directly reducing project budget.

Baking in third-party tools

For high-quality PC VR content, we use Marmoset Toolbag (fast GPU baker, excellent AO with ray-traced shadows) or Substance 3D Painter (for per-object baking in the texturing pipeline). The resulting maps are imported into Unity as Emissive or mixed in a custom shader with a realtime component.

For large scenes — Blender Cycles with denoise (Intel OIDN or OptiX) as an offline baker: slower, but gives cinematic-quality results for cinematic VR experiences.

| Tool | Speed | Quality | Best Use Case |

|---|---|---|---|

| Unity Progressive | Fast | Good | Medium scenes, mobile VR |

| Marmoset Toolbag | Very fast | Excellent | PC VR, high-poly |

| Blender Cycles | Slow | Cinematic | Cinematic VR, pre-render |

Step-by-step lightmap setup for VR

1. Check the UV2 of models: padding at least 4 pixels for a 1024 atlas.
2. Disable specular in baking for mobile platforms.
3. Use OIDN denoiser for GPU Progressive.
4. After baking, check the scene in VR mode via Oculus Link or SteamVR.
5. If necessary, reduce texel size for critical areas.

Estimated timelines

| Scene | Timeline |

|---|---|

| Small interior room | 1–2 working days |

| Medium scene (5–10 zones) | 3–5 working days |

| Large open location | 1–2 weeks |

The cost is calculated individually after an audit of the scene and quality requirements. Contact us for a free audit of your VR scene — we will analyze the current settings and propose optimal baking parameters.