@rocky Do you have a 3D Skybox ?
Any object in the 3D Skybox that cast shadows will have its shadow projected from the 3D Skybox to the map. I just made a drawing to show what exactly it means :
[Blocked Image: http://i.imgur.com/F6wNnsH.png]
Therefore, if your 3D Skybox is not properly placed, an object could cast a huge shadow on your map.
Or maybe as Plat said there's just no light_environment ... ![]()