What determines an objects size in the lightmap

We are currently trying to create Uvs for meshes, and after some experimentation we’ve determined that there a few different things that effect an objects size in the baked lightmap.

  • Scale in lightmap on the renderer
  • An Object transform scale

There is something else that effects an objects size in lightmaps.
I’m think that the mesh bounds size might be effecting it as well but i’m not sure.

Does anyone know for sure what effects an objects size in the lightmap.