TL;DR: Yes, Unity can build a GTA-scale game, but only if you stop using traditional MonoBehaviour patterns. You need Addressables for world streaming, DOTS, ECS, and the Job System plus Havok for physics at scale, tiered NPC simulation, a floating origin system near 5000 meters, and active ragdolls to approximate Rockstar's Euphoria. Content is the real bottleneck.

Can you make GTA 6 in Unity?

Every Unity developer has had this thought at some point: "What if I tried building something like GTA?" We imagine a massive city with cars everywhere, NPCs living their lives, no loading screens, and total chaos when things go wrong. For years, the common answer was that Unity simply could not handle that level of scale and complexity. I do not think that is true anymore, but I also do not think the answer is a simple yes. After spending years working with Unity systems and digging into how engines like Rockstar's RAGE work, my honest opinion is that Unity can build a GTA-scale simulation, but only if you stop thinking in traditional Unity patterns.

World Streaming: Where Custom Engines Still Have an Advantage

One of the biggest technical challenges in an open world game is streaming the world without loading screens. When you fly across Los Santos in GTA V, the engine is constantly loading and unloading assets, but you never really notice it. Rockstar designed their RAGE engine specifically for this type of streaming; the world is divided into hierarchical sectors, and the engine predicts player movement to start loading areas ahead of time.

Unity does not give you this system out of the box, but you can build something similar. The closest equivalent is the Addressables system combined with chunk-based world streaming. My approach would involve dividing the city into blocks or sectors where each sector becomes an Addressable group. These are then loaded and unloaded asynchronously based on player position and velocity. Velocity is key here: if the player is driving at 150 km/h, you need to start streaming assets much earlier than if they are walking. One trick that helps is Mip Map Streaming, which allows Unity to automatically load lower resolution textures for distant objects, saving an absurd amount of VRAM. However, Rockstar's engine still does this better because its entire architecture was designed around it from day one.

Character Physics: Euphoria Is Still Hard to Beat

One of the things that gives Rockstar games their unique feel is Euphoria. If you have ever noticed how NPCs in GTA stumble, reach out for balance, or try to recover when they fall, that is not just animation. It is procedural simulation. Euphoria simulates muscle tension, balance, impact response, and physical reactions in real time.

Unity does not have anything like this built in. What it does have is the ability to combine animation with physics through active ragdolls. The basic idea is that your animation system defines a target pose, and physics joints attempt to follow that pose using joint motors or PID controllers. External forces can disrupt the pose, creating that dynamic reaction feeling. You can build this yourself, but it is a serious engineering project. Plugins like PuppetMaster make it easier, but they still are not quite the same as the proprietary tech Rockstar has refined over decades.

Physics Simulation: Where Unity Starts Catching Up

Sandbox games are physics heavy. Cars collide, props explode, and debris flies everywhere. Unity's default physics engine, PhysX, is very capable, but if you try to simulate hundreds of rigidbodies using classic GameObjects, performance will eventually tank. This is where DOTS (Data-Oriented Technology Stack) and ECS (Entity Component System) start to matter.

With ECS, you stop thinking in terms of objects and start thinking in terms of data. Instead of spawning hundreds of car GameObjects, you create hundreds of entities containing simple data like position, velocity, and direction. Movement systems can then process thousands of entities in parallel using the C# Job System. If you combine this with Havok Physics for Unity, the performance difference is dramatic. This is one area where Unity actually becomes extremely competitive with custom engines, provided you do not fall back on traditional MonoBehaviour patterns. If you are new to these concepts and want a clear path through Unity and C#, my Learn Unity roadmap breaks down systems thinking and fundamentals in a structured way.

Simulating a Living City

A big open world feels alive because there is activity everywhere: pedestrians walking, cars moving through traffic, and small interactions happening constantly. Rockstar solves this with tiered simulation. Distant NPCs are extremely cheap agents with simple behaviors, and as they get closer to the player, they upgrade into fully simulated characters.

This translates well into Unity using ECS for distant simulation. You can run thousands of simple traffic or pedestrian agents with very low CPU cost. Then, when the player gets close, you convert those entities into full GameObjects that use animation, physics, and complex AI. That hybrid model is essential for scaling large worlds without melting the user's hardware.

The Floating Origin Problem

Large worlds introduce the problem of floating point precision. The further objects move away from coordinate (0,0,0), the more physics and rendering start to break down, resulting in "jittery" movement. Rockstar solves this with world rebasing. Instead of the player moving infinitely across the world, the world periodically shifts so the player stays near the origin.

Unity developers typically solve this with a floating origin system. When the player moves far enough from the center (usually around 5000 meters), the entire world shifts back toward zero. It sounds complex, but in practice it is a manageable system. You just have to ensure that objects like particle systems and trails are updated correctly during the shift so they do not appear to "teleport."

AI Systems and the Real Bottleneck

One thing people misunderstand about GTA is the police system. It is not just enemies chasing you, but a global director system managing the response. When a crime is committed, the director spawns police units at valid locations outside the camera view and creates search zones. This is very doable in Unity by using a centralized AI Director rather than putting all the logic inside every agent.

Ultimately, the biggest barrier to building a GTA-style game is not the engine anymore. It is content. Rockstar has thousands of developers creating animations, environments, vehicles, and voice acting. However, AI is starting to change that equation. Procedural asset generation and AI animation tools are improving fast. Within the next decade, we might see small teams, or even solo developers, building indie GTA sandboxes that previously required hundreds of people. For developers who want to level up their systems and architecture skills with direct feedback, 1-on-1 mentorship can help you design these kinds of systems without wasting months on dead ends.

My Final Take

So can Unity build a GTA-scale game? Yes, but only if you treat Unity like a systems engine rather than a beginner-friendly framework. You need to lean heavily into Addressables, ECS, the Job System, and hybrid simulation models. While Rockstar's RAGE still holds specific advantages in world streaming and procedural animation, the gap is closing. The next generation of massive open world games might not just come from the giants, but from developers who know how to push these modern systems to their absolute limit.

Written by Darko Tomic.