MP_Inventory

MP_Inventory is a powerful multiplayer-ready inventory system for Unreal Engine, built with full replication support. It allows storing, managing, and sharing items with a robust tag system, private/public access control, and persistent item data. Designed to simplify multiplayer item management, it's highly modular, extendable, and open-source.

Technologies Used

Unreal Engine 5C++Subsystem-based ArchitectureReplication SystemTag-based Filtering

Plugin Info

Completed

startDate: 2025-03-01

endDate: 2025-04-07

teamSize: 1

role: Lead Developer

engine: Unreal Engine 5.3+

compatibility: Windows, Linux, macOS, PlayStation, Xbox, Mobile

Repository

Gallery

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Advanced inventory management system with tag-based organization

Plugin Specifications

Compatibility Matrix

Windows

Linux

macOS

PlayStation

Xbox

Mobile

Dependencies

Unreal Engine Replication System

API Documentation

Key Functions

UMP_InventoryComponent::AddItem(FMP_ItemData Item, int32 Quantity)

Adds item to inventory with replication support

UMP_InventoryComponent::RemoveItem(FMP_ItemID ItemId, int32 Quantity)

Removes item from inventory with synchronization

UMP_InventoryComponent::ExchangeItem(UPlayerController* TargetPlayer, FMP_ItemID ItemId)

Exchanges item with another player securely

UMP_InventoryComponent::SetItemVisibility(FMP_ItemID ItemId, bool bPublic)

Sets item visibility to public or private in multiplayer world

Integration Guide

Attach MP_InventoryComponent to Player Characters

Set up MP_ItemDefinitionStorage to define items

Use MP_TradingManager for secure trades

Utilize MP_TradeExchange for listing items

Access inventory functions in Blueprints

Key Features

Multiplayer and replication ready inventory system

Persistent storage using subsystem-backed architecture

Advanced tag system for item categorization and filtering

Private and public item visibility control

Item exchange and trading between players

Dynamic economy system with price adjustments based on supply and demand

Product management creating supply and demand for items in multiplayer world

Product management creating supply and demand for items

Historical metadata storage for trade tracking

Weight management for inventory capacity

Multiple inventory support for different contexts

Easy to implement and use in both single-player and multiplayer

Blueprint and C++ API support for flexibility

Technical Challenges

Technical Challenge 1

Problem:

Ensuring reliable synchronization across variable network conditions

Solution:

Implemented replication-based synchronization with validation

Result:

Stable inventory state across all clients and servers

Technical Challenge 2

Problem:

Creating flexible item organization and filtering system

Solution:

Developed comprehensive tag-based system with multiple criteria

Result:

Powerful and intuitive item management and search capabilities

Integration Challenges

Integration Challenge 1

Problem:

Seamless integration with existing multiplayer workflows

Solution:

Created subsystem-based architecture with extensive Blueprint support

Result:

Easy integration into existing Unreal Engine projects

Integration Challenge 2

Problem:

Supporting both single-player and multiplayer use cases

Solution:

Implemented flexible configuration options for different game types

Result:

Versatile system supporting various game development needs

Results Achieved

Successfully implemented subsystem-based inventory system

Created comprehensive tag-based item filtering

Developed secure player-to-player trading functionality

Integrated dynamic economy system with price adjustments

Established persistent item storage with metadata tracking

What I Learned

Subsystem-based architecture in Unreal Engine

Replication systems for multiplayer inventory management

Tag-based item organization and filtering systems

Player-to-player trading mechanics and economy systems

Development Journey

Design Phase: Inventory system architecture and multiplayer requirements

Core Development: Subsystem implementation and replication systems

Features Implementation: Trading, tagging, and persistence features

Testing Phase: Multiplayer synchronization and edge case handling

Completion: Open source release and documentation