In a detailed breakdown, ex-Rockstar Games animator, Mike York, explained the engineering behind the jiggle physics behind Grand Theft Auto 6 that has spawned countless viral clips and memes.

What sounds like a simple feature is actually a sophisticated marriage of two different simulation systems running simultaneously inside the developer's proprietary RAGE engine.

According to York, every character in GTA 6 has an invisible skeleton made of "bones", mathematical points connected in a hierarchy that defines how the character model can move. Your character's spine connects to shoulder bones, which connect to arm bones, and so on. This bone structure is what allows animators to create movement.

But here's where it gets interesting for realistic body physics: Rockstar took it further by animating additional physics-driven bones specifically for soft tissue simulation. These bones aren't manually animated frame by frame. Instead, they respond dynamically to the character's movement using physics calculations.

Using Lucia walking across a yacht in the second GTA 6 trailer, for example, York explains that her main skeleton is following the running animation of an animator creator. But layered on top of that, physics bones are calculating how soft tissue would realistically move based on momentum, gravity, and speed. The RAGE engine is doing these calculations in real-time, every frame, for every character on screen.

York emphasizes that this physics calculation occurs in real time, meaning it's genuinely responsive to what's happening in the game world.

So when you see a GTA 6 trailer scene captured entirely on base PS5 with dozens of NPCs on a beach, each with realistic body physics, you're watching the RAGE engine performing thousands of physics calculations per second across all those characters simultaneously.