Game Physics Engines: What Indie Devs Actually Get to Use

Big-budget games have custom or heavily customized physics; indie teams usually rely on what’s built into their engine. So what do indie devs actually get when they use Unity, Unreal, Godot, or other engines—and where do the limits show up?

What’s in the Box

Most mainstream engines ship with a physics system. Unity uses PhysX (Nvidia); Unreal has Chaos (its own system) and legacy PhysX; Godot has its own implementation. You get rigid-body dynamics, collision detection, triggers, and often ragdolls and joints. For a lot of indie games—platformers, top-down shooters, puzzle games, simple simulations—that’s enough. You don’t have to write a physics engine; you configure it and hook it up to your gameplay. So “what indie devs get to use” is, in practice, a full-featured rigid-body and collision system that handles 99% of what small teams need.

The catch is that “full-featured” doesn’t mean “no quirks.” Each engine has its own behavior, performance characteristics, and bugs. Unity’s PhysX can be finicky with fast-moving objects and thin colliders. Unreal’s Chaos is powerful but has a learning curve and different defaults. Godot’s physics are simpler and sometimes less precise. So indie devs “get to use” the engine’s physics, but they also have to learn its limits and work around them. That’s normal—you’re not expected to drop in a new engine; you’re expected to ship with the tools you have.

Where the Ceiling Is

Indie devs rarely get access to the kind of physics that AAA games use for destruction, cloth, or massive particle systems. Those often require custom or middleware solutions and a lot of tuning. So “what you get to use” is the built-in system—no custom fluid sim, no proprietary destructible-mesh pipeline unless you license it. For most indie projects that’s fine; you’re not building a demolition sim. But if your game idea depends on something the engine doesn’t do well (e.g. precise vehicle physics, complex soft-body), you either simplify the design or look for a plugin or middleware. That’s the real ceiling: you’re working within the engine’s model, not extending it from scratch.

Performance and Scale

2D vs 3D also matters. Many indie games are 2D, and engines offer 2D physics (e.g. Box2D in some engines, or 2D mode in Unity/Godot). The principles are the same—collision, forces, joints—but the workload is lower and the behavior is easier to reason about. So “what indie devs get to use” often means “2D physics that just work” for platformers and top-down games, and “3D physics with some tuning” for anything more complex.

Physics is expensive. Too many rigid bodies, too many collisions, or too many raycasts per frame can tank performance. Indie devs “get to use” the same systems as everyone else, but they have to be careful about object count, complexity, and platform. Mobile and low-end PCs are less forgiving. So the practical limit is often “how much can I simulate at 60 fps on my target hardware?” not “what does the engine support?” The engine gives you the tools; you have to stay within the budget.

Bottom Line

Indie devs get to use mature, capable physics engines out of the box. For typical 2D and 3D indie games, that’s enough. The limits show up when you need something the default system doesn’t do well, when you hit performance walls, or when engine quirks force workarounds. So “what indie devs actually get to use” is a solid, ready-made physics layer—with the understanding that you’re working inside it, not beyond it.