CombineInstance

Description

A struct that describes a single mesh to be merged with other instances into a combined mesh.

Use this CombineInstance struct with the Mesh.CombineMeshes method to merge multiple meshes into a single combined mesh. You must create a CombineInstance for each mesh you want to combine. If a mesh contains multiple sub-meshes, you must create a separate CombineInstance for each sub-mesh.

using UnityEngine;

// This script combines the meshes from children into a single new Mesh.
// The combined mesh is assigned to the MeshFilter of this GameObject.
// The original meshes are not destroyed, but their GameObjects are disabled.

[RequireComponent(typeof(MeshFilter), typeof(MeshRenderer))]
public class ExampleClass : MonoBehaviour
{
    void Start()
    {
        MeshFilter[] meshFilters = GetComponentsInChildren<MeshFilter>();
        CombineInstance[] instances = new CombineInstance[meshFilters.Length];

        for (int i = 0; i < meshFilters.Length; i++)
        {
            var meshFilter = meshFilters[i];
            
            instances[i] = new CombineInstance
            {
                mesh = meshFilter.sharedMesh,
                transform = meshFilter.transform.localToWorldMatrix,
            };

            meshFilter.gameObject.SetActive(false);
        }

        Mesh combinedMesh = new Mesh();
        combinedMesh.CombineMeshes(instances);
        gameObject.GetComponent<MeshFilter>().sharedMesh = combinedMesh;
        gameObject.SetActive(true);
    }
}

Additional resources: Mesh.CombineMeshes, Mesh.subMeshCount.

Properties