You have your normal model (let's call it the "high poly version") which is called "model.fbx", "model_c.png" is the color map, "model_d.png" is the diffuse etc... When you select your model in the importer panel, the game will load the fbx, triangulate, consolidate and do more things of the kind such as calculating tangents/normals if unavailable for your model. It will then load the textures and map them to the preview model. At this stage, if you are pleased with this model and press continue, you will get to the Decoration part of the asset editor and a little task notification in the top corner will notify you it is Compressing the textures and Generating LOD. During that process you can freely start propping and editing value, though you cannot save the new asset until those tasks are finished. In this scenario, the game will create a LOD automatically. Our algorithm does not perform great for every possible shape of buildings, even though most of the time, the LODs are so small when you see them in-game, it is not even that big of a deal. In the case it does not, or in the case you want to do a better job with your own hands. You can model a lod and place it along side the model and call it model_lod.fbx. If you do this, you need to UV map the model but no need to texture it as the game will bake the LOD textures out of the high poly version of the mesh. If you are a purist and you want both the LOD and the LOD textures done by yourself, then just add the model_lod_d.png along side and the game will simply load them.