UE Mass Entity Target engine: UE 5.8 . APIs below are verified against the 5.8 headers; older forms are listed under "Deprecated — do not use". Mass is an archetype Entity Component System for simulating thousands of agents with cache-friendly data layouts and multi-threaded processors. The core lives in the always-available runtime modules and (plus , ); gameplay-facing pieces (spawning, representation, movement, LOD, replication, actor bridging) come from the MassGameplay (Experimental in 5.8) plugin, and navigation/behavior from MassAI (Experimental in 5.8) and MassCrowd (Experimental in 5…