unity-physicscore2d-performance

Spawn batches of dynamic bodies each frame while monitoring world.profile.simulationStep, and stop when the step time exceeds your target millisecond budget for a sustained number of frames. Read final body, shape, and contact counts from world.counters to determine capacity.

Typical targets are 1000-5000 dynamic bodies on desktop and 500-1000 on mobile, depending on collision pair counts and shape complexity. Static bodies are virtually unlimited, while kinematic bodies cost between static and dynamic.

Set startMassUpdate to false in the PhysicsShapeDefinition when adding many shapes to one body, then call body.ApplyMassFromShapes() once at the end. This avoids recalculating mass after every individual shape creation.

Long physics steps usually come from too many active bodies, complex joint networks, high solver iteration counts, or many compound shapes. Reduce collision pairs with layer filtering, simplify geometry, enable sleeping, and lower solver iterations.

Use NativeArray and NativeList with appropriate allocators instead of List<T>, preallocate object pools, and reuse query result containers. Batch body creation and destruction, and always dispose native collections to avoid leaks.

Yes, mobile targets should use lower body counts around 500-1000, simpler collision geometry, aggressive culling, and lower solver iterations. WebGL has similar constraints plus WASM performance and browser memory limits.