void Restore()
{
rootNode = rootNode_backup.Clone();
partNodes = new List <PartNode> ();
foreach (PartNode pn in partNodes_backup)
{
partNodes.Add(pn.Clone());
}
}
void Backup()
{
rootNode_backup = rootNode.Clone();
partNodes_backup = new List <PartNode> ();
foreach (PartNode pn in partNodes)
{
partNodes_backup.Add(pn.Clone());
}
}