Under the Hood: Understanding Unreal Engine and Its Role in Modern Racing Simulations

Unreal Engine: The technology behind modern racing games

The Unreal Engine is one of the most powerful and widely used game-development platforms in the world. It is particularly interesting when discussing racing simulators because it provides developers with an enormous toolkit for creating realistic environments, vehicles, lighting, weather, physics, and interactive worlds.

And here’s something worth understanding right away: Unreal Engine is not a racing game. It’s the technology used to build one.

Think of it as the foundation, construction equipment, electrical system, and plumbing of a house. The developer still has to design and build the house. Having expensive equipment doesn’t automatically make it a good house. The same principle applies to racing games.

1. What exactly is Unreal Engine?

Unreal Engine is developed by Epic Games. Its origins go back to 1998, when Epic released the original Unreal game.

Since then, it has evolved into a sophisticated development platform used for:

• Racing and simulation games.
• First-person shooters.
• Open-world games.
• Flight simulators.
• Architectural visualization.
• Film and television production.
• Virtual production and special effects.

The current generation, Unreal Engine 5, introduced several technologies that have significantly changed what’s possible visually.

But graphics are only one piece of the puzzle.

2. What makes Unreal Engine interesting for racing games?

There are several major components worth understanding.

A. Graphics and environments

Unreal Engine can produce exceptionally realistic environments.

For racing games, that includes:

• Realistic asphalt and dirt surfaces.
• Detailed vehicles and cockpits.
• Trackside buildings and grandstands.
• Dynamic lighting and shadows.
• Weather effects.
• Dust, smoke, tire debris, and particle effects.
• Reflections and environmental details.

Two particularly important UE5 technologies are:

Nanite: Allows developers to use extremely detailed 3D geometry without the traditional level-of-detail compromises that game developers have historically dealt with.

Lumen: A dynamic lighting and global illumination system. It allows lighting, reflections, and indirect illumination to respond to changes in the environment.

For example, imagine a dirt track at sunset. As the sun drops toward the horizon, lighting changes across the track, vehicles, grandstands, and surrounding environment.

That’s the sort of thing Unreal Engine can accomplish.

B. Physics and vehicle simulation

This is where things get considerably more interesting for someone interested in actual racing simulation.

Unreal Engine includes a physics system called Chaos Physics.

Chaos can handle things such as:

• Vehicle suspension.
• Collision detection.
• Rigid-body physics.
• Vehicle movement.
• Deformation and destruction.
• Physical interactions between objects.

However, there’s an important distinction:

Unreal Engine’s built-in vehicle physics does not automatically make a realistic racing simulator.

A developer still has to create or implement the sophisticated vehicle dynamics that make a racing simulation believable.

For example, consider what goes into simulating a dirt late model:

1. Tire grip and slip angles
2. Weight transfer during acceleration and braking.
3. Suspension geometry and travel.
4. Differential behavior.
5. Engine torque and power delivery.
6. Track surface conditions.
7. Tire temperature and wear.
8. Aerodynamics and chassis behavior.

The developer must decide how deeply to simulate these systems.

A game can use Unreal Engine and still have relatively simplistic vehicle physics. Conversely, a developer can build an impressive simulation using Unreal’s rendering and development tools while implementing a highly specialized physics model.

The engine provides the foundation. The developer determines the sophistication.

3. The development tools are a big part of its appeal

One reason Unreal Engine is so popular is that developers don’t have to build every component of a game from scratch.

It includes an extensive collection of development tools.

Blueprints

Blueprints is a visual programming system. Developers can connect nodes representing instructions, conditions, calculations, and actions without writing traditional programming code for every operation.

For example, a developer could use Blueprints to create:

• A pit-lane speed limiter.
• A caution flag system.
• A tire wear interface.
• Track lighting that changes with the time of day.
• AI-controlled competitors.
• Race rules and scoring systems.

More advanced functionality can be programmed in C++, which gives developers considerably more control.

The combination of visual scripting and traditional programming makes Unreal attractive to development teams of different sizes.

The asset marketplace

Unreal also has an extensive ecosystem of third-party assets and tools.

Developers can acquire or purchase:

• 3D vehicle models.
• Buildings and grandstands.
• Trees, vegetation, and terrain.
• Sound effects.
• Animation systems.
• Specialized programming tools.
• Track-building components.

This can dramatically reduce development time.

A small independent developer doesn’t necessarily have to employ an entire modeling department to create every object in a racing environment.

That doesn’t mean the finished product will automatically be good. It means there are fewer mountains to climb before development even begins.

4. What does Unreal Engine mean for a racing simulator?

This is probably the most important part of the discussion.

There are several things that separate a convincing racing simulator from a racing game that merely looks realistic.

Unreal Engine can provide much of the underlying infrastructure, but the development team must implement and tune the simulation.

The dirt racing example

Let’s use a dirt late model because that’s where things get particularly interesting.

Imagine a 30-lap feature.

During those 30 laps:

• The racing surface changes
• The preferred racing groove moves.
• Moisture levels change.
• Rubber and dirt accumulate.
• The track develops rough spots and ruts.
• Tire grip changes.
• Cars begin behaving differently as conditions evolve.

A truly sophisticated dirt racing simulator needs to account for these changing conditions.

Unreal Engine can render the changing surface, simulate physical interactions, and provide the framework for implementing those systems.

But the actual dirt-track simulation model is something the developer must create.

This distinction is critical. A beautiful dirt track with a constantly changing visual surface isn’t necessarily a dynamically simulated dirt track.

One is visual presentation. The other is simulation.

5. Performance: An important consideration for sim racers

Unreal Engine is powerful, but it can also be demanding.

A racing simulator has some unusually difficult performance requirements.

Think about what happens when you have 30 cars on the track:

• Every car has its own physics calculations
• Each vehicle has suspension and tire interactions.
• Cars collide and interact with one another.
• AI competitors require processing.
• The track environment needs rendering.
• Audio and environmental effects are running.
• Multiplayer synchronization may be occurring.

And all of this needs to happen without introducing noticeable delays.

For someone using a steering wheel and pedals, consistency matters enormously.

A game that looks spectacular but produces inconsistent frame rates or sluggish steering response isn’t much of a simulator.

This is especially important for force feedback. The physics calculations and steering response need to be dependable, even when the graphics workload gets heavy.

Epic provides developers with optimization and profiling tools, but the responsibility for making a particular racing game run well remains with its developers.

6. Unreal Engine and other game engines

There are several competing development platforms.

Engine	General characteristics
Unreal Engine	High-end graphics, extensive tools, flexible development
Unity	Flexible development platform, popular with independent developers
Proprietary engines	Built specifically for a particular developer’s requirements

A few familiar racing titles have used proprietary or specialized technology rather than Unreal.

The important point is that the engine itself doesn’t determine the quality of the simulation.

A highly specialized engine developed over many years can be exceptionally good at handling vehicle dynamics. Unreal provides a broad foundation that developers can customize.

Neither approach guarantees a better racing experience.

7. Examples of racing games using Unreal Engine

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8. My biggest takeaway

I would look at Unreal Engine as an opportunity rather than a guarantee.

A small development team using Unreal can potentially produce something that would have required considerably more resources a decade ago.

But there’s a danger in confusing technological capability with development achievement.

The engine might provide:

• Beautiful graphics
• Sophisticated lighting.
• Extensive physics functionality.
• Powerful development tools.
• Multiplayer infrastructure.

It cannot provide the developer’s understanding of how a race car actually behaves on a racetrack.

That knowledge still has to come from somewhere.

For a serious racing simulator, I’d rather have convincing tire physics, accurate vehicle dynamics, excellent force feedback, and believable track behavior than the prettiest grandstands in the history of computer gaming.

The grandstands don’t have to negotiate turn three at 90 mph. The car does.

Further reading

These are worth bookmarking if you want to understand the technology behind modern racing games.

• Unreal Engine 5 official overview: Graphics, Nanite, Lumen, and development capabilities.
• Chaos Physics documentation: The underlying physics systems.
• Chaos Vehicles documentation: Vehicle physics and implementation.
• How Fuse Games uses Unreal Engine 5 for racing: A particularly relevant developer interview.

One thing I’d encourage you to investigate: the relationship between the game engine and the vehicle physics simulation. They’re two very different things, and understanding that distinction will make you a much better judge of racing simulators such as DirtSim, iRacing, and Assetto Corsa.