3D Lighting

Expert guidance for realistic 3D lighting with shadows and global illumination.

NEVER Do

• NEVER use VoxelGI without setting a proper extents — Unbound VoxelGI tanks performance. Always set size to tightly fit your scene.
• NEVER enable shadows on every light — Each shadow-casting light is expensive. Use shadows sparingly: 1-2 DirectionalLights, ~3-5 OmniLights max.
• NEVER forget directional_shadow_mode — Default is ORTHOGONAL. For large outdoor scenes, use PARALLEL_4_SPLITS for better shadow quality at distance.
• NEVER use LightmapGI for fully dynamic scenes — Lightmaps are baked. Moving geometry won't receive updated lighting. Use VoxelGI or SDFGI instead.
• NEVER set omni_range too large — Light attenuation is quadratic. A range of 500 affects 785,000 sq units. Keep range as small as visually acceptable.
• NEVER hide a Light node using the Visible property to exclude it from a Lightmap bake — Hiding a light has no effect on the baker. You must change the light's Bake Mode to Disabled.
• NEVER use VoxelGI with paper-thin walls — VoxelGI evaluates lighting using a 3D grid. Thin walls (less than one voxel thick) will cause severe light leaking. Seal your geometry or place hidden thick MeshInstance3D blocks around the exterior.
• NEVER leave shadow bias at default for cascades — Default bias often causes Peter Panning or light leaking at split transitions. Tune bias per-light based on your scene's scale.
• NEVER bake LightmapGI without a Denoiser — Godot's baked lightmaps are noisy by default. Use OIDN or JNLM (in Project Settings) for professional results.
• NEVER use real-time SDFGI on Mobile/Compatibility renderers — It is a Forward+ exclusive feature. Use fake GI bounce lights for lower-end platforms.
• NEVER use 'Update Continuity' in ReflectionProbes for performance — Keep ReflectionProbes on 'Update Once' and trigger manual updates only when necessary.