Post
Faking real-world physics convincingly enough that your brain does not question it.
Physics engines handle collision detection, rigid body dynamics, ragdolls, cloth simulation, fluid dynamics, and all the other systems that make game worlds feel physically plausible. They do not simulate real physics perfectly -- they approximate it fast enough to run at 60fps. Havok dominated AAA games for years, PhysX became the standard through NVIDIA's backing and its integration into Unity and Unreal, and Bullet powers everything from Blender to robotics simulations. The best physics in games is the kind you never notice because it just feels right.
Example
Half-Life 2 was a landmark for physics in games, using Havok to make its gravity gun a core gameplay mechanic. Picking up radiators to use as shields and launching sawblades at zombies felt revolutionary in 2004 and still holds up.
Why it matters
Physics is what makes game worlds feel tangible rather than like painted cardboard. Without it, objects would clip through each other, characters would float, and destruction would be impossible. It turns virtual spaces into places that feel real.
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