Collision Manager Overview

The Collision Manager is a Blueprint-based system for Unreal Engine 5 projects, designed to handle trace hit detection and target selection for Action RPGs and combat-focused games. It enables developers to manage collision detection for weapons and find targets for Gameplay Abilities and Gameplay Effects without requiring complex collision setups. The system addresses the need for precise, flexible hit detection and targeting, supporting mechanics like melee swings, projectile targeting, and ability lock-on. It targets game developers and designers building combat systems, offering standout features like modular target types, tick-based tracing, and animation-driven collision control.

System Architecture

The Collision Manager is organized around the BP_CollisionComponent, which serves as the central hub for managing collision target types and trace logic. Blueprints handle collision detection, target selection, and integration with other systems like the Advanced Abilities Framework. The system is entirely Blueprint-based, ensuring accessibility for designers and developers without C++ dependencies.

• Key Blueprint Classes:

  • BP_CollisionComponent: Manages collision target types for an actor, enabling hit box creation and target searches. It initializes default target types, activates/deactivates collisions, and handles target queries.
  • BP_TargetType: Base class for collision handler objects, used for custom or one-off target searches, particularly for abilities requiring specific targets.
  • BP_TraceTarget: Base class for trace-based collision handlers, supporting continuous tick-based tracing until deactivated, ideal for persistent hit detection.
  • BP_SweepingSocketTraceTarget: Specialized trace target for melee attacks, using mesh sockets to define precise collision paths for weapon swings.
  • ANS_CollisionTrace: Animation Notify State that activates/deactivates trace collisions during specific animation frames, ensuring precise timing for melee hit boxes.

• Data Flow:

  • Actors (e.g., characters, weapons) possess a BP_CollisionComponent, initialized on BeginPlay with default target types via DefaultTargetTypeMap or DefaultTargetTypes.
  • BP_TargetType or its derivatives (BP_TraceTarget, BP_SweepingSocketTraceTarget) are added to BP_CollisionComponent using AddCollisionTargetType.
  • Collisions are activated/deactivated via ActivateCollisionByTag/DeactivateCollisionByTag or ANS_CollisionTrace, triggering trace logic or target searches.
  • Targets are queried using FindTargetsByClass or GetTarget/GetTargets for ability targeting, with results passed to abilities or effects.

graph TD
    A[Actor] -->|Owns| B[BP_CollisionComponent]
    B -->|Manages| C[BP_TargetType]
    B -->|Manages| D[BP_TraceTarget]
    B -->|Manages| E[BP_SweepingSocketTraceTarget]
    B -->|Uses| F[ANS_CollisionTrace]
    C -->|Extends| D
    D -->|Extends| E
    F -->|Controls| D
    F -->|Controls| E

Core Features

• Trace Hit Detection:
  • Enables weapons to detect hits using trace-based collision without adding BP_CollisionComponent directly to the weapon actor.
  • Benefits: Simplifies hit box setup for weapons, supporting precise collision detection for melee or projectile attacks.
• Target Selection for Abilities:
  • Finds single or multiple targets for Gameplay Abilities and Gameplay Effects using BP_TargetType or trace-based classes.
  • Benefits: Facilitates lock-on mechanics, AoE targeting, or ability-specific target searches, enhancing combat dynamics.
• Modular Target Types:
  • Supports custom BP_TargetType children for one-off searches, BP_TraceTarget for continuous tracing, and BP_SweepingSocketTraceTarget for melee swings.
  • Benefits: Offers flexibility to tailor collision and targeting to specific gameplay needs, reusable across actors.
• Animation-Driven Collision:
  • Uses ANS_CollisionTrace to activate/deactivate trace collisions during specific animation frames, aligning hit boxes with attack visuals.
  • Benefits: Ensures precise timing for melee attacks, improving visual and gameplay fidelity.
• Configurable Collision Parameters:
  • Provides properties like Collision Radius, Collision Object Types, and Gameplay Tags to Ignore to customize trace behavior.
  • Benefits: Allows fine-tuned control over what collisions detect, reducing false positives and enhancing performance.
• Sweeping Melee Support:
  • BP_SweepingSocketTraceTarget uses mesh sockets for accurate melee swing traces, with adjustable trace paths and collision properties.
  • Benefits: Delivers realistic weapon collision for melee combat, supporting varied attack animations.