Lightmap storage
These Baker controls change the next bake. They do not recompress or repack an existing saved result.
BakerResolution Scale
Default: 1. Accepted range: 0.05 to 4; slider range: 0.1 to 2.
Multiplies the lightmap resolution used for the bake. At 1, the bake uses the authored resolution. Lower values reduce surface detail and cost; higher values capture finer lighting at greater texture and bake cost.
Resolution is a length in each texture dimension. Doubling it can require roughly four times as many texels for the same surface. Bake Mode: Fast applies its own reduction on top of the authored scale.
This setting does not change probe spacing. Use Lightmaps to change selected meshes' UV layout or authored resolution.
LightmapsPacked Lightmap Texture Size
Choices: 256, 512, 1024, 2048, 4096.
Sets the target size of packed lightmap atlas textures. Multiple mesh lightmaps can share an atlas. The value is synchronized with the current level's World Settings, so the displayed value can differ between maps.
Larger atlases change how lightmaps are grouped into textures; they do not grant every mesh more lightmap detail. A mesh still needs suitable UVs and resolution. Inspect the actual texture count and memory after baking rather than treating atlas size as a quality preset.
Compression
Default: Smooth.
Uncompressed
Stores the lightmap coefficient data without block compression, using BGRA8 data. Preserves that data more directly at a substantially higher texture-memory and storage cost. It is useful as a comparison when deciding whether visible artifacts come from compression.
Smooth
Uses BC7 compression. This is the default balance between texture size and smooth lighting detail. Inspect low-contrast gradients and broad surfaces when comparing against Uncompressed.
Compact
Uses BC7 for irradiance and a smaller BC1 representation for directional data, with conservative compression optimization. This reduces storage at the cost of some directional fidelity. It is not simply a lower bake sample count.
Use Memory to compare actual results. Saved package size and fully loaded GPU memory are different measurements.
Suggest Generated Lightmap UV Upgrades
Default: disabled. Advanced control.
Allows bake preparation to offer upgrades for older engine-generated lightmap UV layouts. Custom-authored layouts are skipped.
This is an offer to update eligible generated layouts, not a blanket replacement of every mesh's UVs. Updating a layout changes where lighting belongs in the texture and invalidates existing baked lighting for it.
A generated UV upgrade changes the mesh asset used by its instances. Review the affected assets and rebake the lighting that depended on their old layout.
UV Seam Stitching
Strength
Default: 0. Minimum: 0; slider up to 4, with no declared hard maximum.
Controls how strongly eligible UV seams are stitched during the bake. At 0 stitching is disabled. Increase it when matching surfaces still show a visible lighting discontinuity across a UV seam.
Stitching is a continuity adjustment, not a replacement for valid UV islands, padding, or enough texels.
Cosine Normal Threshold
Default: 0.95. Range: 0 to 1. Used when Strength is above 0.
Controls how closely the normals on the two sides must agree for stitching. A higher threshold accepts only more similarly facing surfaces. A lower threshold permits a wider change in angle.
Keep this distinction in mind at deliberate hard edges: forcing unlike surfaces to share lighting can remove a real change in shading.