Optimize physics query performance and reduce garbage collection overhead by using efficient query versions and batch processing.
Standard physics queries, such as Physics.Raycast, Physics.SphereCast, or Physics.OverlapSphere, allocate memory on the heap for their results. This allocation can contribute to garbage collection pauses, especially if they are called frequently.
Instead, use the non-allocating counterparts of these queries that write their results into a pre-allocated array that you provide. Non-allocating counterparts can include:
For example:
int hitCount = Physics.RaycastNonAlloc(ray, preAllocatedHitsArray, distance, layerMask);
When you use non-allocating queries, you must provide a pre-allocated array. For example, RaycastHit[] preAllocatedHitsArray = new RaycastHit[10];.
Size this array appropriately: make it large enough to capture the maximum expected hits in typical scenarios, but not so large as to waste memory. If the number of actual collidersAn invisible shape that is used to handle physical collisions for an object. A collider doesn’t need to be exactly the same shape as the object’s mesh - a rough approximation is often more efficient and indistinguishable in gameplay. More info
See in Glossary found exceeds the size of your buffer array, only the results up to the array’s capacity are returned, and the rest are ignored.
Tip: Choose a buffer size that balances typical needs with memory considerations. Profile your game to understand common hit counts.
Running many individual physics queries (for example, many raycasts per frame) can reduce performance because of the overhead of each call. If you need to perform many queries simultaneously, batch them using APIs like RaycastCommand, SpherecastCommand, or BoxcastCommand in conjunction with the job system.
This approach leverages multi-threading to process queries in parallel, significantly improving performance for bulk query operations. This is particularly powerful when you have many independent raycasts (or other queries) that can be processed in parallel.
To use batch queries, follow these steps:
NativeArray<RaycastCommand> with the parameters for all your raycasts.NativeArray<RaycastHit> to store the results.RaycastCommand.ScheduleBatch, which returns a JobHandle.jobHandle.Complete before you access the results. For example, ensure the job is complete at the start of the next frame or when needed.