There are two versions of building prefabs: -The first version: With optimization scripts If you want to use the optimization script, use these prefabs. HPA > Prefabs > Buildings > With_Optimization -The second version: Without optimization scripts If you don't want to use the optimization script, use these prefabs HPA > Prefabs > Buildings > Without_Optimization For more information about optimization script included in the asset please read documentation chapter 12 HPA > Documentation > Documentation.pdf