UEDEV / 3D Navigation AI / Crowds · Updated
v3.6.0 Use case · Mass crowds
Mass Entity flying crowds for Unreal Engine 5
Drone swarms, bird flocks and fish schools in true 3D through Unreal's Mass ECS — 10,000+ agents on per-agent paths or one shared flow field, with crowds that perch, scan, engage, investigate and flee.
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- LCM 3D Navigation AI
- Unreal Engine 5.2–5.8
- Mass Entity agents
- 10,000+
- Mass traits
- 8
- Mass StateTree nodes
- 13
- Flow-field sampling
- O(1)
Per-agent paths or one shared flow field
Crowds heading the same way sample one shared CPU flow field in constant time, while the agents that matter get their own asynchronous paths. Auto-registered processors handle request, solve and steer, so you never call the solver yourself. A crowd's first flow field is built off the game thread, so a crowd spawning into a streamed world does not cost one long frame.
Crowds that behave, not just move
Ten Mass StateTree tasks and three evaluators let crowds perch, scan, engage, investigate and flee. Agents in a crowd share the work: they sweep an area sharing the viewpoints, close round an intruder the moment any of them sees it, and no two take the same perch, cover or vantage point.
Dense crowds that do not overlap
Hold Avoidance Between Scans keeps separation on every frame, and Contact Push pushes apart bodies that overlap — including agents that have arrived — so a crowd no longer piles onto its goal. A crowd agent pushed off the flow field's covered space steers back instead of freezing, and schooling works for Mass crowds as well as pawns.
One trait, no code
Add a trait to a Mass Entity Config and the crowd navigates in full 3D, with no per-agent controller and no tick function. Eight traits cover movement, guidance, goals, perception, behaviour status and rendering, and an editor validator flags illegal combinations — the one rule is exactly one movement trait per agent. Crowds render through instanced meshes with LOD representation.
See it in the demo levels
These levels are part of the 57 free demo levels you download from inside the editor (LCM Nav3D menu › Get the Demo Levels).
Hunter Pack
Five Mass drones hunt as a pack through the container terminal.
- Mass StateTree
- Engage
Reef School
A school of forty follows its lead fish on the flow field.
- Schooling
Sentry Swarm
Six Mass drones guard a depot as one, then rest on the pads.
- Scan Area
- Perch
Warehouse Security
Four Mass security drones watch, sweep, engage and search.
- Investigate
Raider Swarm
Eighteen raiders sweep the asteroid belt and close round fighters.
- Engage
Vertical Skyscraper
A crowd threading a tower interior, floor by floor.
- Flow field
Common questions
How many agents can navigate in 3D through Mass Entity?
10,000 or more. Crowds can use per-agent asynchronous paths or one shared flow field that the whole swarm samples in constant time, and they render through instanced meshes with LOD.
Do I need C++ to use Mass crowds?
No. Add the traits to a Mass Entity Config; an editor validator flags illegal trait combinations, and Mass StateTree tasks drive the behaviour.
Can crowds use behaviours like perch and engage?
Yes. Ten Mass StateTree tasks and three evaluators let crowds perch, scan, engage, investigate and flee, and agents share viewpoints, perches and cover so no two take the same one.
Read more in the free documentation:
