Physics.BakeMesh

Parameters

Description

Prepares the Mesh for use with a MeshCollider.

This function runs Mesh baking and saves the result in the Mesh itself. When a MeshCollider referencing this Mesh is instantiated, it reuses the baked data instead of re-baking the Mesh. This is useful when you want to move the expensive baking process from the Scene load time or instantiation time to a different moment in time. BakeMesh is thread-safe, and does computations on the thread it was called from. You can use BakeMesh with the C# job system. Here is an example:

using UnityEngine;

public class MinimalTest : MonoBehaviour
{
    public Mesh mesh;

    private MeshCollider collider;

    private void OnEnable()
    {
        // Bake this Mesh to use later.
        Physics.BakeMesh(mesh.GetInstanceID(), false);
    }

    public void FixedUpdate()
    {
        // If the collider wasn't yet created - create it now.
        if (collider == null)
        {
            // No mesh baking will happen here because the mesh was pre-baked, making instantiation faster.
            collider = new GameObject().AddComponent<MeshCollider>();
            collider.sharedMesh = mesh;
        }
    }
}

BakeMesh is thread-safe, and does computations on the thread it was called from. You can use BakeMesh with the C# job system. This example shows how to bake meshes across multiple threads so that MeshCollider instantiation takes less time on the main thread.

using Unity.Collections;
using Unity.Jobs;
using UnityEngine;

public struct BakeJob : IJobParallelFor
{
    private NativeArray<int> meshIds;

    public BakeJob(NativeArray<int> meshIds)
    {
        this.meshIds = meshIds;
    }

    public void Execute(int index)
    {
        Physics.BakeMesh(meshIds[index], false);
    }
}

public class JobifiedBaking : MonoBehaviour
{
    public Mesh[] meshes;
    public int meshesPerJob = 10;

    // Bake all the Meshes off of the main thread, and then instantiate on the main thread.
    private void OnEnable()
    {
        // You cannot access GameObjects and Components from other threads directly.
        // As such, you need to create a native array of instance IDs that BakeMesh will accept.
        NativeArray<int> meshIds = new NativeArray<int>(meshes.Length, Allocator.TempJob);

        for (int i = 0; i < meshes.Length; ++i)
        {
            meshIds[i] = meshes[i].GetInstanceID();
        }

        // This spreads the expensive operation over all cores.
        var job = new BakeJob(meshIds);
        job.Schedule(meshIds.Length, meshesPerJob).Complete();

        meshIds.Dispose();

        // Now instantiate colliders on the main thread.
        for (int i = 0; i < meshes.Length; ++i)
        {
            new GameObject().AddComponent<MeshCollider>().sharedMesh = meshes[i];
        }
    }
}