I did those environment assets in early 2017 working on a mobile project. Our art direction was to create Warhammer series look for mobiles platform. All assets are heavily optimized for mobile platforms. Most assets don't exceed 2000 triangles per object. Textures are packed together to improve performance. This project was very interesting to me because I had opportunity to work on in-house mobile engine. It was heavily optimized and we had simplified PBR rendering calculated in real-time on metal. Rendering quality of the engine is easily one of the top on mobiles.