Attributes of objects can be placed in the modeling area which allows them to emphasize additional, important aspects in the model.
A symbol can be placed instead of a value for some attributes, which allows the attribute value to be identified immediately.
If such an attribute was specified and placed, for example, the Existence attribute, the As a symbol check box becomes available. If you enable the check box, a plus sign is placed in the model instead of Yes for the Existence attribute, and a minus sign instead of No.