Baking lights

Hello,
can anybody help me with problem about baking the lights. I have a few tree prefabs but I can’t bake lights for all of them. All trees are marked as static (lightmap static), also they are marked Cast Shadows in Mesh Render. A few tree prefabs I have created by duplicating other prefab, than I edited those…

The Console is telling this: “Secondary UV set on Mesh is incorrect. Lightmapper needs UVs inside the [0,1]x[0,1] range. Skipping this mesh…
Choose the ‘Generate Lightmap UVs’ option in the Mesh Import Settings or provide proper UVs for lightmapping from your 3D modelling app”

How can I fixe UVs for tree prefabs, which are created in Unity3D?

Thank you very much, for help
Jirka[14503-snímek+obrazovky+2013-08-19+v+9.46.06.jpg|14503]

Check the following! Are the trees casting a shadow (imported models, like an .OBJ file or so)?
Imported models, do have a setting for Generate Lightmap UV:s.

Do this:

  • Click on the model (that cast shadows) in the Project Window!
  • Check the Inspector Window, under Model
  • There you should find a checkbox for Generate Lightmap UVs

If the tree is (for example created in Unity) it doesn´t have this option to be checked.

Now do the same thing and check if the tree that doesn´t have a shadow, if it has the option checkbox for Generate Lightmap UVs or not.

I don´t know of a way (in the Free Unity version) to have shadows from trees made by Tree Creator. If someone does, plz give us help.