GregOrigin - BlueLine: Smart Tagging & Node Alignment

andgregori · January 26, 2026, 4:48am

BlueLine is a lightweight, modular C++ plugin for Unreal Engine 5 designed to solve three specific problems in professional development workflows:

Graph Readability: Replaces messy Bezier "noodles" with clean, 90-degree orthogonal wiring without the performance cost of A* pathfinding.
Team Collaboration: Provides "Soft Formatting" tools that align nodes without reorganizing the entire graph, preventing massive Git/Perforce diffs.
Data Visualization: Transforms standard Gameplay Tags in the Details Panel into colored, readable chips, synchronized across the entire team via Data Assets.

🔌 Graph Enhancements

BlueLine replaces the standard graph rendering pipeline with a high-performance "Manhattan" style renderer.

1. Manhattan Wiring

Orthogonal Routing: Wires turn at 90-degree angles.
Ghost Wires: Wires passing behind nodes are automatically rendered with reduced opacity (35%) to reduce visual noise.
Performance: Uses simple geometric heuristics instead of pathfinding, ensuring zero input lag even in massive Animation Blueprints.

2. "Soft Magnet" Formatting (Shift + Q)

Unlike other auto-formatters that rearrange your entire graph (destroying your specific layout), BlueLine uses a Selection-Only approach.

Usage: Select a group of nodes and press Shift + Q.
Behavior: Nodes align grid-relative to their input connections.
The "Anti-Diff" Philosophy: BlueLine never touches nodes you haven't selected. This ensures your Commit History remains clean and readable.

3. Hotkeys

Key Action Description Shift + Q Magnet Align Aligns selected nodes to the grid relative to their inputs. F8 Toggle Style Instantly switches between BlueLine wires and Standard Bezier curves.

🏷️ Smart Tags & Visualization

BlueLine overrides the Details Panel customization for FGameplayTag, replacing the text string with a colored "Chip" widget.

1. Setup (Team Color Sync)

Colors are not stored in local user preferences. they are stored in a Data Asset so the whole team sees the same colors.

Create a DataAsset derived from BlueLineThemeData.
Name it DA_BlueLineDefault and place it in /Game/BlueLine/ (Content/BlueLine/).
- Note: This path ensures the plugin finds it automatically without configuration.
Add Tag Styles:
- Tag: Status.Debuff
- Color: Red
- Apply To Children: True
- (Result: Status.Debuff.Fire and Status.Debuff.Ice will automatically inherit Red).

2. Runtime Debugging (C++)

Debug colors shouldn't disappear when you hit PIE (Play In Editor). Use the static library to draw colored tags on the HUD or in World space.

3. Blueprint Support

The library is exposed to Blueprint as "Draw BlueLine Debug Tag".

andgregori · February 20, 2026, 7:45am

I’m posting a changelog here for clarity

BlueLine Changelog

Bug Fixes

Fixed Pin Duplication in Demo Nodes

Fixed a critical bug where AllocateDefaultPins() was not clearing existing pins before creating new ones, causing duplicated/stacked pins to appear when nodes were reconstructed (e.g., during compilation or undo/redo).

Affected Files:

Source/BlueLineSmartTags/Private/Demos/UK2Node_TagDemo.cpp
Source/BlueLineSmartTags/Private/Demos/UK2Node_KingSafety.cpp
Source/BlueLineSmartTags/Private/Demos/UK2Node_AWSTag.cpp

Fix: Added Pins.Reset() at the beginning of AllocateDefaultPins() to clear existing pins before recreation.

Fixed F8 Key Binding Conflict

Changed ToggleWireStyle command from F8 to Shift+F8 to avoid conflict with Unreal Engine's built-in "Possess or Eject Player" debugger command used in Play-in-Editor (PIE) mode.

Affected Files:

Source/BlueLineGraph/Private/Commands/FBlueLineCommands.cpp
Source/BlueLineGraph/Private/BlueLineGraphModule.cpp
Source/BlueLineGraph/Public/Commands/FBlueLineCommands.h

New Shortcut:

Shortcut	Command	Context
`Shift+F8`	Toggle Wire Style	Blueprint Graph

Fixed Hardcoded Stub Length

The FBlueLineConnectionPolicy was using a hardcoded stub length value (20.0f) instead of respecting the user-configurable StubLength setting from Editor Preferences.

Affected Files:

Source/BlueLineGraph/Private/Drawing/FBlueLineConnectionPolicy.cpp

Fix: Changed from hardcoded value to use Settings->StubLength:

// Before:
const float StubLength = 20.0f * LocalZoomFactor;
// After:

const float StubLength = (Settings ? Settings->StubLength : 20.0f) * LocalZoomFactor;

Improvements

Implemented WireStyle Support

The WireStyle setting (Thin/Medium/Thick/Dynamic) in Editor Preferences was previously defined but not actually applied to wire rendering. Now it's fully functional.

Affected Files:

Source/BlueLineGraph/Private/Drawing/FBlueLineConnectionPolicy.cpp

Implementation:

void FBlueLineConnectionPolicy::DetermineWiringStyle(UEdGraphPin* OutputPin, UEdGraphPin* InputPin, FConnectionParams& Params)
{
    // Applies WireStyle from settings:
    // - Thin: 1.5px
    // - Medium: 2.5px  
    // - Thick: 4.0px
    // - Dynamic: Uses theme-based type coloring
    // Also applies WireThicknessMultiplier setting
}

Removed Ghost Setting: bAnimateExecutionWires

Removed the bAnimateExecutionWires setting from Editor Preferences that had no implementation. This was a placeholder setting that had no effect.

Affected Files:

Source/BlueLineCore/Public/Settings/UBlueLineEditorSettings.h
Source/BlueLineCore/Private/Settings/UBlueLineEditorSettings.cpp

New Feature: Graph Bookmarks

Added bookmark system for quick navigation in Blueprint graphs.

Hotkeys:

Ctrl+1-9: Set bookmark at selected node
1-9: Jump to bookmark
Ctrl+0: Clear all bookmarks in current graph

Features:

Bookmarks persist per graph across editor sessions
Stored in Saved/BlueLineBookmarks.json
Automatic cleanup when assets are deleted
Visual feedback in Output Log

New Files

Source/BlueLineGraph/
├── Public/Bookmarks/
│   └── FBlueLineBookmarkManager.h      # Bookmark management API
└── Private/Bookmarks/
    └── FBlueLineBookmarkManager.cpp    # Implementation with JSON persistence

New Feature: Node Snippets

Save selected nodes as reusable templates that can be quickly inserted into any graph.

Hotkeys:

Shift+S: Create snippet from selected nodes
Shift+I: Insert a saved snippet

Features:

Full node serialization including connections
Organize snippets by category
Persistent storage in Saved/BlueLineSnippets.json
Export/import snippets for sharing

New Files

Source/BlueLineGraph/
├── Public/Snippets/
│   └── FBlueLineSnippetManager.h       # Snippet management API
└── Private/Snippets/
    └── FBlueLineSnippetManager.cpp     # Implementation with JSON persistence

[1.0.3] - 2026-02-09

Overview

Major feature release introducing BlueLineRuntime - a new runtime module that enables Blueprint Subsystem creation directly from the editor. This release also adds the "Extract to Subsystem" feature, allowing developers to refactor complex Blueprint graphs by extracting selected nodes into dedicated Subsystem Blueprints.

New Module: BlueLineRuntime

Blueprint Subsystem Base Classes

The BlueLineRuntime module provides Blueprint-friendly base classes for creating Unreal Engine Subsystems without writing C++. This enables developers to create managers and systems that persist across level transitions using familiar Blueprint workflows.

New Files

Source/BlueLineRuntime/
├── BlueLineRuntime.Build.cs              # Module build configuration
├── Public/
│   ├── BlueLineRuntimeModule.h           # Public module interface
│   └── Subsystems/
│       ├── BlueLineGameInstanceSubsystem.h   # GameInstance base class
│       ├── BlueLineWorldSubsystem.h          # World base class
│       └── BlueLineLocalPlayerSubsystem.h    # LocalPlayer base class
└── Private/
    ├── BlueLineRuntimeModule.cpp         # Module implementation
    └── Subsystems/
        ├── BlueLineGameInstanceSubsystem.cpp
        ├── BlueLineWorldSubsystem.cpp
        └── BlueLineLocalPlayerSubsystem.cpp

Base Classes

Class	Parent	Use Cases
`UBlueLineGameInstanceSubsystem`	`UGameInstanceSubsystem`	Game state managers, Save/load systems, Achievement managers
`UBlueLineWorldSubsystem`	`UWorldSubsystem`	Level-specific rules, World event managers, Per-level audio
`UBlueLineLocalPlayerSubsystem`	`ULocalPlayerSubsystem`	Per-player input, Player UI controllers, Split-screen HUD

Blueprint Events

All base classes provide Blueprint-implementable events:

On Initialize - Called when subsystem is initialized
On Deinitialize - Called when subsystem is shut down
On Post Initialize (World only) - Called after all subsystems initialized
On World Begin Play (World only) - Called when world starts gameplay
On Update Streaming State (World only) - Called for streaming updates

New Feature: Extract to Subsystem

Shift+B: Extract Selected Nodes to Subsystem

A powerful refactoring tool that allows extracting selected Blueprint nodes into a new dedicated Subsystem Blueprint. This helps organize complex graphs by isolating functionality into properly architected subsystems.

How It Works

Select nodes in any Blueprint graph
Press Shift+B or right-click → "Extract to Subsystem"
Choose destination in the save dialog
New Blueprint created inheriting from BlueLineGameInstanceSubsystem
Blueprint opens automatically for editing

Implementation

New Files:

Source/BlueLineGraph/Public/BlueprintSubsystem/BlueprintSubsystemExtractor.h
Source/BlueLineGraph/Private/BlueprintSubsystem/BlueprintSubsystemExtractor.cpp

Key Features:

Analyzes selected nodes for external connections and dependencies
Creates properly configured Blueprint with correct parent class
Supports fallback to engine subsystem classes if BlueLineRuntime unavailable
Opens save dialog for user to choose destination path
Automatically opens new Blueprint for editing

Build System Updates

BlueLineRuntime.Build.cs (New)

public class BlueLineRuntime : ModuleRules
{
    PublicDependencyModuleNames.AddRange(
        new string[] { "Core", "CoreUObject", "Engine" }
    );
}

BlueLineGraph.Build.cs

 PrivateDependencyModuleNames.AddRange(
     new string[]
     {
         // ... existing modules ...
+        "ContentBrowser",   # Required for save asset dialog
+        "AssetTools"        # Required for blueprint creation
     }
 );
+// Allow includes from BlueLineSmartTags without circular dependency

+PrivateIncludePathModuleNames.AddRange(

new string { "BlueLineSmartTags" }

);

Plugin Configuration

BlueLine.uplugin

{
    "Version": 3,
    "VersionName": ",
    "Modules": [
        { "Name": "BlueLineCore", "Type": "Runtime", "LoadingPhase": "PreDefault" },
        { "Name": "BlueLineRuntime", "Type": "Runtime", "LoadingPhase": "Default" },
        { "Name": "BlueLineGraph", "Type": "Editor", "LoadingPhase": "PreDefault" },
        { "Name": "BlueLineSmartTags", "Type": "Editor", "LoadingPhase": "Default" },
        { "Name": "BlueLineLevel", "Type": "Editor", "LoadingPhase": "PostEngineInit" }
    ]
}

Keyboard Shortcuts

New Commands

Shortcut	Command	Context	Module
`Shift+B`	Extract to Subsystem	Blueprint Graph	BlueLineGraph
`Shift+E`	Export to Text	Blueprint Graph	BlueLineGraph

Updated Shortcuts Reference

Shortcut	Command	Context
`Shift+Q`	Auto-Format Graph	Blueprint Graph
`Shift+R`	Rigidify Connections	Blueprint Graph
`Shift+C`	Clean Graph	Blueprint Graph
`Shift+T`	Auto-Tag Selection	Blueprint Graph
`Shift+B`	Extract to Subsystem	Blueprint Graph
`Shift+E`	Export to Text	Blueprint Graph
`Shift+S`	Open Level Pie Menu	Level Editor Viewport
`Shift+F8`	Toggle Wire Style	Blueprint Graph

New Feature: Export to Text

Shift+E: Export Blueprint to Readable Text

A lightweight text exporter that converts Blueprint graphs into human-readable format for debugging, documentation, and AI-assisted analysis. Inspired by the Blueprint Text Exporter plugin.

How It Works

Open any Blueprint graph
Press Shift+E or right-click → "Export to Text"
Choose save location in the file dialog
Open the .txt file for debugging or AI analysis

Example Output

=== Blueprint Export: BP_Player ===
Export Type: Full Graph
Total Nodes: 42
Event BeginPlay

└─ then →

Set Max Health (MaxHealth = 100.0)

└─ then →

Set Current Health (CurrentHealth = MaxHealth)
Event TakeDamage

Take Damage (Damage = 10.0, DamageType = DamageType_Fire)

└─ then →

Apply Damage (Target = Self, BaseDamage = Damage)

└─ then →

UpdateHealthBar (Percent = CurrentHealth / MaxHealth)

Implementation

New Files:

Source/BlueLineGraph/Public/Export/BlueLineGraphExporter.h
Source/BlueLineGraph/Private/Export/BlueLineGraphExporter.cpp

Key Features:

Exports full graph or selected nodes
Follows execution flow with tree structure
Expands pure (data) nodes inline
Saves to [Project]/BlueprintExports/ by default
Compatible with AI tools (ChatGPT, Claude, etc.)

Build System Updates

BlueLineGraph.Build.cs (Updated)

 PrivateDependencyModuleNames.AddRange(
     new string[]
     {
         // ... existing modules ...
+        "DesktopPlatform"   # Required for save file dialog
     }
 );

Context Menu Additions

Blueprint Graph Context Menu

New entries in the "BlueLine Graph" section:

Auto-Tag Selection - Tag selected nodes semantically
Extract to Subsystem - Create subsystem from selection
Export to Text - Export graph to readable text

API Additions

// BlueprintSubsystemExtractor.h
class FBlueprintSubsystemExtractor
{
    bool ExtractToSubsystem(
        UEdGraph* SourceGraph,
        const TArray<UEdGraphNode*>& SelectedNodes,
        ESubsystemType SubsystemType,
        const FString& NewSubsystemName,
        const FString& DestinationPath);
void OpenExtractionDialog(UEdGraph* Graph, const TArray&lt;UEdGraphNode*&gt;&amp; SelectedNodes);
static bool CanExtractNodes(const TArray&lt;UEdGraphNode*&gt;&amp; SelectedNodes);

};
// BlueLineGraphExporter.h

class FBlueLineGraphExporter

{

static void ExportGraphToText(UEdGraph* Graph, const TArray<UEdGraphNode*>& SelectedNodes);

static bool CanExportNodes(const TArray<UEdGraphNode*>& Nodes);

};
// ESubsystemType enum

UENUM()

enum class ESubsystemType : uint8

{

GameInstance,

World,

LocalPlayer

};

Documentation

HTML Manual Updates

Comprehensive documentation updates for the new features:

New Sections Added:

Extract to Subsystem (Shift+B) - Complete workflow guide with visual examples
Export to Text (Shift+E) - Feature documentation with example output
Blueprint Subsystems - Base class documentation with comparison table

Updated Architecture Diagram:

Added BlueLineRuntime module to the dependency graph
Shows Editor → Runtime relationships with dashed lines

New Navigation Items:

"Advanced 🆕" section in sidebar
Individual pages for each new feature

Visual Improvements:

Feature cards for Extract to Subsystem and Export to Text in Overview
Version banner updated
Subsystem type comparison table

Bug Fixes

Fixed circular dependency between BlueLineGraph and BlueLineSmartTags modules
Fixed include paths for cross-module header access
Fixed missing includes in BlueprintSubsystemExtractor (UBlueprintFactory, UEdGraphNode_Comment)

[1.0.2] - 2026-02-08

Overview

Major release introducing BlueLineLevel - a unified Level Editor toolkit previously known as "Shift+S". This release merges the viewport-based modeling workflow tools into BlueLine, creating a complete editor enhancement suite covering both Blueprint graphs and Level Editor viewports.

New Module: BlueLineLevel

Full Migration of Shift+S (ShiftSDev) Plugin

The Shift+S plugin has been fully integrated into BlueLine as the BlueLineLevel module. All functionality has been preserved and enhanced to work within the BlueLine ecosystem.

New Files

Source/BlueLineLevel/
├── BlueLineLevel.Build.cs              # Module build configuration
├── Public/
│   ├── BlueLineLevelModule.h           # Public module interface (IBlueLineLevelModule)
│   ├── BlueLineLevelTypes.h            # Core types (EBlueLinePivotTarget, constants)
│   ├── BlueLineLevelOps.h              # Pivot and selection operations
│   └── BlueLineLevelSelection.h        # Session-based selection system
└── Private/
    ├── BlueLineLevelModule.cpp         # Module implementation
    ├── Core/
    │   ├── BlueLineLevelOps.cpp        # Pivot snapping, vertex picking, material selection
    │   └── BlueLineLevelSelection.cpp  # Cached selection with live preview
    ├── Framework/
    │   ├── BlueLineLevelCommands.h     # Command definitions
    │   └── BlueLineLevelCommands.cpp   # Alt+S shortcut binding
    └── UI/
        ├── SBlueLineLevelPieMenu.h     # Radial pie menu widget
        └── SBlueLineLevelPieMenu.cpp   # Menu implementation

Features Migrated

Feature	Description	Shortcut
Pie Menu	Radial menu for quick actions	`Alt+S`
Pivot Center	Snap pivot to selection center	Pie Menu ↑
Pivot Bottom	Snap pivot to selection bottom	Pie Menu ↓
Cursor Snap	Vertex-precision picker mode	Pie Menu →
Select Scope	Material-based radius selection	Pie Menu ←
Radius Scroll	Adjust selection radius with mouse wheel	While hovering Select Scope

Update: Streamlined Pie Menu Design (2026-02-08)

The Pie Menu has been completely redesigned to match BlueLine's elegant Blueprint aesthetic:

Feature	Implementation
Blueprint Grid Background	Subtle Blueprint-style grid that fades toward edges
Animated Hover States	Smooth interpolation for scale and glow effects
Directional Layout	Clean 90° orientation (Top/Right/Bottom/Left)
Color-Coded Options	BlueLine blue for pivot tools, Greg green for selection, warm accent for cursor
Dynamic Center Indicator	Center dot changes color to match hovered option
Connection Lines	Subtle lines connecting center to each option
Refined Typography	Short labels when idle, full labels on hover
Picker Mode	Minimal crosshair with contextual hints

Visual Hierarchy:

Center dead zone prevents accidental triggers
45° diagonal zones are neutral (no selection)
Options activate only when hovering the specific quadrant
Glow effects provide visual feedback without clutter

andgregori · March 3, 2026, 11:00am

BlueLine 1.0.5 - Changelog

New Features

Magnetic Wire Snapping: Implemented a Node Graph Assistant-style wire snapping system (FBlueLineWireSnapper). When dragging a connection, your cursor will now magnetically snap to valid nearby pins, preventing near-misses during fast routing.
- Configurable via Editor Preferences (Enable/Disable and Snap Radius tuning).

Bug Fixes

Context Menu Crash: Fixed an IsValid() assertion crash (FBlueLineGraphMenuExtender.cpp:120) that occurred when opening the Blueprint right-click context menu immediately at Editor startup before the BlueLineSmartTags module had fully initialized.
Hotkey Conflict: Changed the "Toggle Wire Style" hotkey from Shift+F8 to Shift+W to prevent overriding Unreal Engine's default Play in Editor (PIE) / Eject Player bindings.
Smart Tag Specificity: Fixed an issue where Smart Tag colors could apply the wrong hierarchical style based on string length. The resolver now correctly uses Unreal's native MatchesTagDepth to ensure exact parent-child inheritance logic.
Auto-Routing Tangling: Changed the default value of "Auto-Route New Connections" from true to false to prevent internal macro/node structures from tangling when duplicating or pasting large graphs.

Architectural Improvements

Zero Runtime Overhead: Completely removed the BlueLineRuntime module. The plugin is now 100% Editor-only.
- The "Extract to Subsystem" feature has been rewritten to inherit directly from Unreal Engine's native subsystem classes (UGameInstanceSubsystem, UWorldSubsystem, ULocalPlayerSubsystem) instead of relying on a proprietary BlueLine base class.
Dynamic Configuration: Removed the legacy BlueLineConfig.h constants system. All core thresholds and "magic numbers" have been fully migrated into UBlueLineEditorSettings, ensuring seamless live-updates when modifying preferences.
Version Sync: Aligned BlueLine.uplugin version strings (1.0.5) to accurately reflect documented feature sets.