public void SmoothTerrain(Vector3 pos, int size)
{
int offset = 0;
Vector4 terrainPosition = GetTerrainPosition(pos - terrain.transform.position, size, out offset);
float[,] heights = terrain.terrainData.GetHeights((int)terrainPosition.x, (int)terrainPosition.y, (int)terrainPosition.w, (int)terrainPosition.z);
heights = terrainToolkit.Smooth(heights, (int)size);
terrain.terrainData.SetHeights((int)terrainPosition.x, (int)terrainPosition.y, heights);
}