Advanced gameplay architecture for Mass Entity and StateTree. Featuring a custom C++ movement system, resource/gathering logic, and seamless transitions between Mass and Blueprint Actors. Now includes features for Multiplayer Horde Tower Defence.

Simulate 10,000+ active units at 60 FPS with full StateTree-driven logic, including melee and ranged combat, no C++ required.

Designed for high-density, systems-heavy genres like RTS, Colony Sims, and City Builders, with the raw performance capability to drive thousands of units for Horde and Musou-style combat simulations.

IMPORTANT: As this plugin is still in development, if you need features or support, please contact me on Discord.

Mass Entity + StateTree + Replication is not an officially supported Unreal workflow yet. SMB provides a C++ native and blueprint-usable extensible implementation.

Some features:

• Data-Oriented C++ Processors: High-speed native core.

• Blueprint Managers & Tasks: Simple high-level control.

• StateTree Entity Evaluation: Scalable, complex AI behaviours.

• Zero-Stutter Mass/Actor Syncing: Seamless interaction transitions.

• Bandwidth-Optimized Target Replication: Efficient server-authoritative movement using sparse target-based updates. (Experimental and very limited)

Current work in progress:

• Basic Network Replication for functional movement and interactions.

• Horde Shooter demonstration.

UPDATES:

V0.2.0:

• Experimental Replication: Movement, Spawning, Damage, and Death functionality.

• Large Animation Performance Improvement for 20k entities: Animation is now ~3.3ms from 11.4ms.

• Horde Shooter example, including LOD priority on the center of the camera, allowing Blueprint actors for easy high-quality interaction.

• Added rectangular formation, to be expanded in V0.2.1.

• Various bug fixes, and more.

V0.1.3: (Including V0.1.2.1-5 patches)

• Reworked Movement System: Complete overhaul of movement, higher precision movement, enabling future updates like NavLink, custom movement styles. Default includes acceleration, turn rate, max speed.

• Advanced Animation Baking: Support for additional animation overrides, enabling fully customised animations using the StateTree.

• Additional animation blending: Idle, Walk and Run animation blending depending on speed.

• Smart Object & Resource System: Full integration for Gather, Pickup and Store behaviours. Added interfaces to allow efficient resource transfer and blueprint actor interactions.

• StateTree Improvements: More tasks and conditionals, including checks for Blueprint SmbSubsystem changeable Aggresion Statues like Passive/Patrol/Guard.

• Various bug fixes, performance improvements, and more.

V0.1.2: (Including V0.1.1.1 patch)

• Mass Walk Target Replication: Early-stage replication implementation started, now supports client-side walking directed by servers, server-side spawning; experimental base implementation. Note: Do not use Mass BP Actors with replication yet.

• Mass Synced Blueprint Actors: Blueprint actors controlled by Mass now have no transition. Close-range full blueprint damage is implementable, with any blueprint collision needed. Examples to come.

• Reworked Combat: Fully reworked combat to use processors, greatly improving performance in combat situations.

• Various bug fixes and performance improvements, with more.

V0.1.1: (Including V0.1.0.1 patch)

• RTS Demonstration Level: Added a full RTS example, building system, resources, entity spawning, buildings, wave spawning, and more.

• New Material Baking Process: Materials now use normal materials, only requiring one node to be added for world position offset for a fully functional VAT.

• Healthbars, performant height checks, and more.

View full changes in the changelog.

For game designers

Customise and simulate the behaviour of thousands of units with various types and capabilities using Blueprints, with no need for writing C++ code.

For programmers and 3D artists

Quick setup and efficient animation using Vertex Animation Textures (+ blending, LOD, and Nanite support) while keeping steady 60fps with thousands of units on screen.

Trailer, demo, docs, support

• Watch the trailer

• Download the tech demo or jam game from Itch

• Read the docs

• Join the Discord server for support and feature requests

Core features

• MassEntity Integration: use Blueprints & StateTree to simulate thousands of lightweight units efficiently with ECS-based logic.

• VAT Animation Rendering: efficient animations using Vertex Animation Textures with blending, and Nanite support.

• Easy VAT bake: effortless texture setup and one-click bake.

• StateTree Behaviour Control: define custom AI behaviour (idle, move, attack, etc.) - examples included.

• Data-Driven Abilities: build and customise unit abilities using Data Assets (range, damage, VFX, SFX, animation type, etc.).

• Unit Selection & Commands: RTS-style box select to move command.

• Customisable Unit Types: configure unique units with their own stats, StateTrees, and animation sets.

Performance tested with a laptop using an i7-12700H CPU and a 3070 Ti Laptop GPU with 1080p and high settings and Nanite ISM.

Roadmap

The plugin is actively maintained. I’m working towards V1.0.0 with plans for supporting an even larger scale of entities and enabling multiplayer. I’m happy to accommodate feature requests: please join the Discord to discuss the roadmap in detail.