public float lightmapResolution { get; set; }

The Lightmap Resolution property determines the texel density of the lightmap generated by Unity’s Baked Global Illumination system. It controls the quality of baked lighting by adjusting the resolution of the lightmap in texels per world unit. Higher values improve the visual fidelity of baked lighting, but also increase the time and system resources required to generate lightmaps, and their memory footprint.

Use this property when you need precise and high-quality baked lighting for static objects in a scene.

You can monitor the Occupied texels count in the statistics area at the bottom of the Lighting window to evaluate the impact on the lightmap size.

When Unity serializes this object as a Lighting Settings Asset, this property corresponds to the Lightmap Resolution property in the Lighting Settings Asset Inspector.