Sets the distance (in texels) between separate UV tiles in lightmaps. (Editor only).
The range is 2 to 100. The default value is 2.
This setting can be useful when scaling lightmaps down to support lower-end hardware, which can lead to bilinear filtering issues between neighbouring object's tiles. Adjust this setting to increase the space between tiles, and avoid this issue. Note that adjusting this setting does not affect bilinear filtering within the tile itself.
This setting affects lightmaps generated by the Baked Global Illumination system.
When Unity serializes this LightingSettings object as a Lighting Settings Asset, this property corresponds to the Lightmap Padding property in the Lighting Settings Asset Inspector.
Additional resources: Lighting Settings Asset.