I gave the cabinet example as simple demonstration. I want to be able to modify the symbols without creating new ones.please let me know what are the advance method are. I am trying to create units for closet system. The closet systems do not have back, but the cabinet tool comes with back. i can create a double hanging unit with modifying the base unit, but in-order two delete the back and installing hanging rod i can not modify the cabinets so i need to create symbols by building the unit from scratch.