Unlearning OOP: Data-Oriented Gameplay Design with ECS and Mass Entity | Unreal Fest Chicago 2026

Unreal Engine’s Mass Entity Framework offers incredible performance scaling but unlocking its full potential requires more than just learning a new API—it demands a fundamental shift in how we architect gameplay.

For decades, the industry has relied on Object-Oriented Programming (OOP), where individual actors or game objects manage their own state, leading to complex dependencies and inefficient code that doesn’t scale well on modern multicore processors.

This session recorded at Unreal Fest Chicago 2026 challenges that ingrained mindset by exploring how to apply Data-Oriented Design (DOD) patterns to gameplay systems with UE’s Mass Entity Framework.

We dissect the architectural differences between traditional Actor-based patterns and Mass Entity’s data-first approach, using a practical Combat Positioning system as a case study to demonstrate how to refactor complex, shared-state behaviors into streamlined Entity Component System (ECS) patterns.

We move away from the “Manager” pattern, where objects request permission to act via API calls, and toward independent processors that react to data composition in bulk, eliminating the black-box dependencies that preclude safe parallelism.

The talk covers the specific implications of designing gameplay systems for Mass. Whether you are a technical designer or a gameplay engineer, you will come away with a concrete roadmap for breaking out of the OOP box to build cleaner, safer, and more performant gameplay systems in UE5.

Find out more about Unreal Engine’s Mass Entity Framework here: dev.epicgames.com/documentation/unreal-engine/mass-entity-in-unreal-engine

#MassEntity, #DataOrientedDesign, #EntityComponentSystem, #UnrealEngine, #UnrealFestChicago2026