Mesh.RecalculateBounds

Description

Recalculate the bounding volume of the Mesh from the vertices.

After modifying vertices you should call this function to ensure the bounding volume is correct. Assigning triangles automatically recalculates the bounding volume.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void Start() {
        Mesh mesh = GetComponent<MeshFilter>().mesh;
        mesh.RecalculateBounds();
    }
}

Note: The bounds of a SkinnedMeshRenderer can only be changed by setting the SkinnedMeshRenderer.localBounds.