Bill of Materials Column Properties
You can view, change, or insert the following BOM column properties:
Custom Property
Equation,
you can use the equation
editor to define column-based calculations
on BOM cells
Unit of Measure,
for indicating units of measure for parts in a BOM
Part Number
Item No.
Quantity,
if your BOM does not already have a Qty.
column
Component
Reference
To access the Column
type and Property name
lists:
Double-click the top of a BOM column, just above the column heading.
A dialog box appears above the column with the Column
type and Property name
lists.
To set a BOM column heading to a custom property:
Select Custom
Property from the Column Type
list.
Select a custom property from the Property
Name list.
To set a BOM column heading to an equation that operates
on BOM column cells:
Select Equation
from the Column Type list.
Click Equation 
.
Enter an equation.
To set a BOM column heading to Unit:
Select Unit of
Measure from the Column Type
list.
Select Unit of
Measure from the Property Name
list.
To set a BOM column heading to Part Number:
Select Part Number
from the Column Type list.
Optionally check
Use title summary to enter part numbers by summary name.
To set a BOM column heading to Item No.:
Select Item No.
from the Column Type list.
Type the first item number in the Start
field.
The item number increments by 1 unless you
change the increment.
Type the item number increment in the Increment
field.
Optionally select Follow
assembly order 
to reorder items in a drawing to
follow the assembly from which it is created.
The BOM automatically updates when you reorder
items in an assembly. For components with multiple instances in the BOM,
the first instance appears in the order in which it appears in the FeatureManager
design tree. Subsequent instances increment the quantity.
When you select Follow
assembly order, you cannot group, reorder, or sort items in the
BOM.
Optionally select Do
not change numbers 
to retain original item numbers
after reordering a row.
To set a BOM column heading to Qty. if your BOM does
not already have a Quantity column:
Select Quantity
from the Column Type list.
Select configurations from the Configurations
list.
To set a BOM column heading to Component Reference:
In Column type, select Component Reference.