Surface Tree
From Mod Wiki
A Surface Tree (.sft file) is a set of nodes containing references to textures, roads, stamps and projectors used to create a MegaTexture for a terrain mesh.
A surface tree is needed if your map contains a terrain model. You can create a surface tree using editWorld's Terrain Editor.
Do not edit .sft files manually, since they are generated by editWorld and will be overwritten every time the Terrain Editor content is saved.
