Red Faction: Guerrilla

Buildings fall when a layer's strength drops below the weight above it. Each building is hundreds of destructible parts, each with a weight and a strength, grouped into layers like a stack of pancakes. Destroying parts lowers a layer's strength until it can no longer hold everything above it, and those upper layers turn into loose physics objects.

Concrete pillars are far stronger than glass, and bridges and overhangs need more complex layer groupings. Other games use rules that feel arbitrary: Teardown drops an object only once it is fully cut off from the ground, so a huge building can hang on one strand of voxels, and Battlefield: Bad Company 2 plays a canned collapse after enough prefab pieces break. The core question: "is the strength of one layer greater than the weight of the all the layers above it?"

Falling debris deals damage, so one collapse can trigger the next. When a layer fails, the top of a building can crush the floors beneath it or tip sideways and punch a hole in a neighbouring structure. The cost is a slow stress calculation, so buildings sometimes fall late.

Going frame by frame, you can see the moment the upper layers switch from static geometry to physics pieces. The system ran on a PlayStation 3, hardware over a decade old.

The stress system held up well enough for The Finals to copy it. The Finals, directly inspired by Volition's work, uses a system "basically identical to Red Faction": buildings of hundreds of fractured parts that collapse when a layer's load exceeds its strength.

Running on Unreal Engine 5 and PhysX, with far more memory than an Xbox 360 had, it scales the approach up to destroying whole arenas in a multiplayer match. Earlier, Red Faction on the PlayStation 2 used live mesh cutting to carve spheres out of walls.