Physics NonAlloc

Unity’s standard physics query methods (like Physics.OverlapSphere) are convenient but contribute to memory fragmentation.

The Problem

Methods like OverlapSphere or RaycastAll return a new array of results every time they are called. This array must be allocated on the heap and subsequently cleaned up by the Garbage Collector.

void Update() 
{
    // ❌ Allocates a new array every frame!
    var hits = Physics.OverlapSphere(transform.position, 10f); 
}

The Solution

Unity provides “NonAlloc” versions of these methods (e.g., OverlapSphereNonAlloc). These methods take a pre-allocated array as a parameter and return the number of results found, without creating any new memory.

Collider[] results = new Collider[10];

void Update() 
{
    // ✅ Reuses the 'results' array. Zero allocations.
    int count = Physics.OverlapSphereNonAlloc(transform.position, 10f, results);
}

How Code Hygienist Helps

Detection: Flags standard physics methods used in Update loops.
Guidance: Provides a template and explanation on how to transition to the NonAlloc pattern with pre-allocated buffers.