Block out light

Hi all, is there a way to block out light with a mesh? if i put the “Sun block mesh” to static i get one extra lightmap, and that i dont want. the mesh isent supposed to show up in the final game, so i will turn it off after lightmapping.

To be more specific. I want an object to affect the lightmaps of other objects(i.e cast shadows) without getting a lightmap of its own.

You can set the lightmap scale of your blocker object to 0, that way it will not be placed on any lightmap but will influence the lightmaps of other objects in your scene.