An optional, standalone toolbox: message bus, player classes, modular actors and editor tools. No Crimson plugin requires it.
Free · Toolbox · Unreal Engine 5
An optional toolbox. Take what you need; no plugin requires it.
A gameplay-tag message bus, CommonGame-style player classes with session and user subsystems, Game-Feature-ready modular actors, logging macros, and editor tools including the in-editor Crimson wiki. Every Crimson plugin runs without it; enable it for the pieces your project wants.
Why CrimsonCommon
Independent, opt-in pieces you would otherwise write yourself. Use one, use all, or skip it entirely.
Nothing depends on it
Every Crimson plugin builds and runs on its own with only engine plugins. CrimsonCommon is a toolbox you enable when one of its pieces saves you work, not a foundation you must install first.
Modular base classes
Game-Feature-ready Character, Pawn, Player Controller, Player State, Game Mode/State and AI Controller bases register as ModularGameplay component receivers, so Game Feature actions can add components at runtime. A drop-in for Epic's ModularGameplayActors.
Tag-routed message bus
UCrimsonMessageSubsystem sends struct payloads on gameplay-tag channels with exact or partial matching, so sender and receiver never reference each other. Blueprint gets Listen For Crimson Messages and Broadcast Message nodes.
CommonGame-style player classes
A game instance, local player and player controller that raise reliable controller, player state and pawn set delegates. CallAndRegister_* fires at once when the object already exists, so late binders never miss the event.
Session and user subsystems
UCrimsonSessionSubsystem hosts, finds and joins sessions. UCrimsonUserSubsystem handles login, privileges and the player lifecycle, on OSSv1 or OSSv2 through a compile-time switch.
Editor tools
The in-editor Crimson wiki renders the docs for every Crimson plugin. Alongside it: the DevTools Gallery, a Common Maps toolbar dropdown for the levels you open most, and a widget authoring library that prunes dead animation bindings.
A closer look
Enable it in a minute, remove it just as fast
Tick CrimsonCommon in Edit → Plugins and restart. Blueprint projects need nothing else; C++ projects add one module line. No other Crimson plugin pulls it in or breaks without it.
- The Crimson Wiki button appears on the Level Editor toolbar
Crimson.DevTools.Galleryopens the dev-tool component gallery- The player classes and modular actors are optional extra steps
One channel tree for events from many systems
Every Crimson plugin reports its events through delegates on the object that owns them. When you would rather listen in one place, forward those delegates onto the bus and subscribe by tag.
- Exact or partial matching: listen to a channel or its whole subtree
- Blueprint Broadcast Message takes any struct payload
- The bus is local to one game instance; it does not replicate
Player lifecycle events you can bind late
The engine has no clean "player state arrived" event. UCrimsonCommonLocalPlayer raises controller, player state and pawn set delegates, and the session and user subsystems use these classes to follow each player.
UCrimsonCommonGameInstanceis abstract: subclass it in Blueprint or C++ACrimsonCommonPlayerControllerraises the three local-player delegates
Adopt incrementally: it's a toolbox, not a pipeline
Every piece is independent and opt-in: reparent the Character today and the Player State later, use the message bus without the player classes, or enable the plugin only for the wiki and editor tools. Take only what your game needs.
Technical details
- Engine
- UE 5.8
- Tested platforms
- Windows
- Blueprint-ready
- Yes
- C++ required
- No
- Network replicated
- No
- Dependencies
- ModularGameplay, GameFeatures, GameplayAbilities, EnhancedInput, CommonUI, OnlineSubsystem, OnlineSubsystemUtils, SlateIM, GameplayTagsEditor
Frequently asked questions
Is it really free?
Does it depend on other Crimson plugins?
Do I need C++ to use it?
CRIMSON_LOG_* macros and the dev-tool component library are for C++ authors.Will adopting it change how my game runs?
What does it replace?
Take the pieces you want
CrimsonCommon is free and fully optional. Enable it for the message bus, the player classes, the modular actors or just the in-editor wiki.
Ready for more? Add a premium system
Every premium system runs on its own, so add only the ones your game needs.
Replicated, GAS-native skill trees with a two-graph editor.
- Two-Graph Editor
- Material Splines
- Server-Authoritative
- Atomic Respec & Loadouts
A full Gameplay Ability System layer for UE5.
- Custom ASC & Abilities
- Slot-Based Augments
- Modifiers & Phases
- Graph-Based Combos
Layout-agnostic, fully replicated inventory with bags and containers.
- Pluggable Topology
- Runtime Constraints
- Scoped Containers
- No RPCs to Write
Keybound, paged action bars over a replicated binding store.
- Automatic Stance Pages
- Pluggable Providers
- Server-Validated Edits
- Layout Editor
- UI-Agnostic Snapshots