@grinseengel... it isnt that complicated... Just import your Mesh into Blender, add an "edge split" Modifier to your Mesh, apply it and export the Model... Done...
Image where to find this option:
regards Sebastian
Tutorials: [Blender]Terrain creation ENG/GER [Blender]Low Poly Tree Modeling [GIMP]Create a Texture for Terrains CLICK HERE