Mesh.CombineMeshes

【Mesh.CombineMeshes】

　　public void CombineMeshes(CombineInstance[] combine, bool mergeSubMeshes = true, bool useMatrices = true, boolhasLightmapData = false);

combine	Descriptions of the Meshes to combine.
mergeSubMeshes	Defines whether Meshes should be combined into a single sub-Mesh.
useMatrices	Defines whether the transforms supplied in the CombineInstance array should be used or ignored.

　　Combining Meshes is useful for performance optimization.

　　If mergeSubMeshes is true, all the Meshes are combined to a single sub-Mesh. Otherwise, each Mesh goes into a different sub-Mesh. If all Meshes share the same Material, set this to true.

　　If useMatrices is true, the transform matrices in CombineInstance structs are used. Otherwise, they are ignored.

　　

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(MeshFilter))]
[RequireComponent(typeof(MeshRenderer))]
public class ExampleClass : MonoBehaviour {
    void Start() {
        MeshFilter[] meshFilters = GetComponentsInChildren<MeshFilter>();
        CombineInstance[] combine = new CombineInstance[meshFilters.Length];
        int i = 0;
        while (i < meshFilters.Length) {
            combine[i].mesh = meshFilters[i].sharedMesh;
            combine[i].transform = meshFilters[i].transform.localToWorldMatrix;
            meshFilters[i].gameObject.active = false;
            i++;
        }
        transform.GetComponent<MeshFilter>().mesh = new Mesh();
        transform.GetComponent<MeshFilter>().mesh.CombineMeshes(combine);
        transform.gameObject.active = true;
    }
}