There is also another factor of the separate static meshes is that, when static meshes merged, the material slots with the same material are merged forming a single one, the amount of material slots decreased, the less material slots the greater the performance, I already recreated the interior of my space more than 9 times and so far I have not achieved success in obtaining quality and performance, the unreal engine is completely limited, apparently if I use low poly to optimize I will have a game-like game in the years of 2013, as games so light and so big in the open world and with hight poly objects in high quantity and rendered at such a great distance, with epic lighting and effects Ex: Shadow Of Tomb Raider can run on my PC with the graphics in ultra and all effects including can ray tracing and post processing on ultra run so lightly and at 60 FPS on my PC without loss of system performance? And in my project I put a simple Hight poly corridor with 30 material slots and the FPS drops easily to 30 and degradatively drops until the game does not become playable with very few resources.