Desert rocks pack with 33 rock models, nice terrain with 4 different desert materials.
Each model have 4 LOD stages. In example video, with baked lightmaps, FPS is very high, over 400FPS.
Small rocks are atlased to only 2 textures, which ensures fast rendering with very few drawcalls.
Few triangle count examples: Gate: 17K (LOD1: 11K, LOD2: 8K, LOD3: 3K, LOD4: 600 tris).
Gate2: 11K (LOD1: 8K, LOD2: 8K, LOD3: 1K, LOD4: 500 tris)
Small Rocks (7pcs): from 200-500 triangles, usually you use them to paint on terrain.
RockSet8: 5K (LOD1: 3K, LOD2: 3K, LOD3: 1K, LOD4: 500 tris)
RockSet9: 3,8K (LOD1: 2.9K, LOD2: 1.8K, LOD3: 400, LOD4: 100 tris)
Rest of rocks are usually 3K triangles with 4 LODS inside.