Grand Theft Auto Relied on "Illusions" Over Simulation, According to Obbe Vermeij

In Part 1 of our exclusive interview with former Rockstar North technical director Obbe Vermeij, he revealed that Grand Theft Auto III began development before it was even formally approved, among other curious tidbits. In this second installment, we turn from origin stories to craft. Specifically, how early GTA games created the illusion of life, and why that illusion still matters more than brute-force simulation.

There is a moment every Grand Theft Auto player recognizes, even if they struggle to put it into words. You step onto the pavement, traffic rolls by, someone mutters under their breath, and a scrap of paper drifts across the street. Nothing spectacular is happening. Yet the city feels alive. According to former Rockstar North technical director Obbe Vermeij, that feeling was never about brute-force simulation or overwhelming technical complexity. It was about illusion.

When asked about technical tricks players rarely notice, Vermeij didn’t point to advanced AI systems or massive background simulations. He talked about litter.

From the things I worked on I would say the litter in the streets made a huge visual difference without people noticing it too much. Papers get pulled along in the slipstream of cars. It doesn't look like much but without it the world looks sterile.

It’s a small detail. Most players would never consciously register it, but remove it, and something feels wrong. During the development of Grand Theft Auto III and Grand Theft Auto: Vice City, environmental touches like this quietly carried enormous weight.

Another example was even subtler. Point the camera directly at the sun and the screen darkens slightly.

If you point the camera at the sun, the screen goes 20% darker. Nobody notices it but they do squint their eyes.

It’s not physically accurate light simulation. It’s perceptual guidance. A minor shift in brightness nudges the brain into accepting the scene as believable without requiring expensive systems running in the background - and it wasn’t just one developer obsessing over tiny details.

Everybody on the team had details that they put in. It was really fun to see the city ‘full up’ with character during development.

When asked whether illusion, density, or systemic simulation mattered most in building that feeling, Vermeij was direct.

If you can do something with illusion then that's preferable.

He pointed to an example from Grand Theft Auto IV. At night, headlights could be seen moving along distant roads, suggesting flowing traffic. In reality, there were no fully simulated cars attached to them. A handful of moving lights were enough to sell the idea, and the player’s mind did the rest.

As fidelity rises, the margin for error shrinks. Modern hardware allows for detailed models, advanced lighting, and complex animations. Yet when asked what truly breaks immersion today, Vermeij didn’t hesitate.

In terms of fidelity I would say NPC AI and animation is the thing that breaks the illusion more than anything. It doesn't matter that your models look photo realistic if an NPC walks into a wall.

Interestingly, Vermeij did not identify early technical constraints as happy accidents that improved design. Instead, he pointed to friction.

What was different was that mission failure actually had a price. You had to go back and pick up weapons etc. I find it a little annoying how modern games (not only GTA 5) are so easy. When you're damaged you just have to wait a second to regain full health.

As expectations continue to rise, maintaining the illusion becomes more demanding. The challenge for modern open-world games is not simply building something larger or more detailed, but preserving that fragile sense of life as the technical bar climbs ever higher.