API Reference

Core types

Type	Category	Description
`UCrimsonSkillTree`	Asset	Tree data asset - nodes, graph config, presentations, connection paths
`UCrimsonSkillTree_Node`	Asset	A single node - costs, activation conditions, node events, state
`UCrimsonSkillTree_Edge`	Asset	Directed edge; per-edge conditions, events, color overrides, LOD
`UCrimsonSkillTreeManager`	Runtime	Replicated component: budgets, levels, RPCs, loadouts, save data
`UCrimsonSkillTreeBlueprintLibrary`	Runtime	BP helpers - node lookup, cost formatting, simulation

Host contract

The actor that hosts a UCrimsonSkillTreeManager must implement `ICrimsonSkillTreeInterface` (all three methods are BlueprintNativeEvent). The manager calls these on its owning actor to resolve the logical effect owner; without the interface, initialization fails (crash in development builds, silent no-op in shipping - see Quick Start step 2).

Method	Returns / purpose
`GetSkillTreeOwner()`	The actor that logically owns the tree's effects - typically the controlled Pawn/Character
`GetSkillTreeOwnerCharacter()`	The owning `ACharacter` (used by character-scoped events such as float-property modifiers)
`GetSkillTreeManagerComponent()`	The host's `UCrimsonSkillTreeManager` instance

Sub-node bases

Type	Purpose
`UCrimsonSkillTree_ActivationConditionBase`	Prerequisite check before a node activates
`UCrimsonSkillTree_NodeEventBase`	Effect fired on level-up / level-down / reset
`UCrimsonSkillTree_EdgeConditionBase` / `UCrimsonSkillTree_EdgeEventBase`	Edge-scoped condition / event
`FNodeResourceCost` / `FNodeCostDefinition`	A cost (flat or curve-scaled) and its resource source

Connection line styles

Type	Description
`UCrimsonSkillTreeWidget_LineDrawingPolicyBase`	Abstract, swappable connection-line strategy (`GraphConfig.LineDrawingPolicy`)
`USkillTreeLineDrawingPolicy_StraightLine` / `_ElbowLine`	Built-in straight and elbow styles
`UCrimsonSkillTreeWidget_ConnectionLayer`	Single runtime widget that paints every connection (material-capable strip or anti-aliased polyline)
`FCrimsonSkillTree_ConnectionPath`	Per-connection authored path (anchors, material, shape curve) on `ConnectionPaths`
`ECrimsonConnectionAnchorMode`	Attach mode enum

Widgets

Type	Description
`ICrimsonSkillTreeNodeWidget`	The node contract. Implement on any `UUserWidget` to use it as a node - no plugin base class required. `UCrimsonSkillTreeWidget_Node` is a ready-made implementation you may subclass instead (`On Update Node Appearance` / `On Node Hovered`)
`ICrimsonSkillTreeDecorationWidget`	The decoration contract (panel / header / divider) - `InitializeSkillTreeDecoration`. The host resolves the class from the decoration's `WidgetClassOverride`, else `GraphConfig.DecorationWidgetClasses[Kind]`. `UCrimsonSkillTreeWidget_Decoration` is the ready-made implementation
`UCrimsonSkillTreeUIStatics`	Blueprint helpers a node needs without inheriting anything - `Request Skill Node Action`. `UCrimsonSkillTreeWidget_NodeTooltip` remains available as a ready-made tooltip
Screen + canvas	You build these - see How-To: Display the Skill Tree. A prebuilt `UCrimsonCoreSkillTreeScreen` / `UCrimsonCoreSkillTreeGraph` also exists (CrimsonCore - requires all Crimson plugins), listed for orientation only

Runtime structs & enums

Type	Description
`FSkillNodeChangeRequest`	A single node action in a batch (`NodeGuid` + `ActionType`)
`FSkillTreeLoadout`	Named snapshot of node levels in a tree
`FCrimsonSkillTree_SaveGameData` / `_SaveGameNodeState`	Plain save structs (in `CrimsonSkillTree_SaveData.h`)
`FCrimsonSkillTree_VisualDecoration` / `ECrimsonSkillTree_VisualDecorationKind`	One authored decoration on `UCrimsonSkillTree::Decorations` - `Kind`, `GamePosition`, `GameSize`, `DisplayText`, `TintColor` (multiplies the widget's authored color; white = as authored) and the optional `WidgetClassOverride`. Panel / Header / Divider
`ECrimsonSkillNodeActionType`	Activate / Deactivate / IncrementLevel / DecrementLevel
`ECrimsonNodeState`	UnSet / Set / Max / Suppressed

Config & extension

Type	Description
`UCrimsonSkillTreeSettings`	Project Settings -> Crimson -> Crimson Skill Tree
`UCrimsonGameFeatureAction_AddSkillTrees`	Game Feature action injecting a tree into an actor at runtime

Built-in node events & conditions

Type	Effect / Check
`UCrimsonSkillTree_NodeEvent_ApplyGameplayEffect`	Applies/removes a GE scaled to the node level
`UCrimsonSkillTree_NodeEvent_GrantGameplayAbility`	Grants/removes a Gameplay Ability
`UCrimsonSkillTree_NodeEvent_ModifyCharacterFloatProperty`	Adds/subtracts a named float property on the owner
`UCrimsonSkillTree_ActivationCondition_ParentLevel`	Parent node at/above a minimum level
`UCrimsonSkillTree_ActivationCondition_AttributeRequirement`	A GAS attribute meets a threshold
`UCrimsonSkillTree_ActivationCondition_ResourcePointsSpent`	A minimum number of points spent in the tree
`UCrimsonSkillTree_Condition_CompositeBase` (+ `_AND` / `_OR`)	Combine conditions with AND / OR

Connection visual states

Type	Purpose
`ECrimsonConnectionVisualState`	Locked / Unlockable / Active / Maxed - resolved from live node data
`FCrimsonConnectionLineStyle`	Per-state look: color, thickness, brush (material-capable), opacity
`FCrimsonConnectionFillSettings`	Progress-fill animation (FillAlpha material parameter, duration, easing, line-split fallback)
`FCrimsonConnectionTransitionSettings`	State crossfade (duration, easing, optional material parameter)
`FCrimsonConnectionHoverSettings`	Runtime hover (tolerance px, hover style, blend time)
`UCrimsonSkillTreeWidget_ConnectionLayer`	Single widget painting all connections; hover hit-testing + `OnConnectionHoverChanged`
`UCrimsonSkillTreeWidget_LineDrawingPolicyBase::ResolveConnectionState/Style`	State + style resolution (override points for custom policies)
`CrimsonSpline::BuildShapedPolyline`	Chord + perpendicular shape-curve polyline (fixed 0..1 domain, endpoints pinned to the anchors)

System readiness

Announced as a ModularGameplay feature state: UGameFrameworkComponentManager::ChangeFeatureInitState(Actor, CrimsonSkillTreeTags::SystemReadyFeatureName, Manager, TAG_Crimson_SystemReady_SkillTree), with SystemReadyFeatureName = "Crimson.SystemReady.SkillTree". Wait on it rather than polling for the component: RegisterAndCallForActorInitState(Actor, CrimsonSkillTreeTags::SystemReadyFeatureName, FGameplayTag(), Delegate, true) (C++), or read the manager with GetImplementerForFeature.

Tag constant	Tag	Announced when
`CrimsonSkillTreeTags::TAG_Crimson_SystemReady_SkillTree`	`Crimson.SystemReady.SkillTree`	Announced once the manager exists, has its configured trees assigned, and is registered.