A calculation modifier is a value or formula you can add to the area and perimeter values of each boundary of a space to modify values for certain calculations. For example, you can specify a 3% plaster deduction for all interior walls, or calculate a balcony at only 50% of its square meters for renting. 
- In Style Manager, create a new calculation modifier style. 
 
- Define a formula with which to calculate the value of the base area or base perimeter of the space. 
 
 
- Add the calculation modifier to a space or to a zone. 
 
 
- To apply the modifier to the net, usable, and gross boundaries of a space, create and apply a property set definition that contains properties for the calculated area and perimeter values of the net, usable and gross boundaries. . 
 
- Use the modified values in a schedule table or in a space evaluation.