Right-click a virtual component in the browser, and choose Component Settings from the menu.
In the Component Settings dialog box, enter a new component name.
In the Bill of Materials section,
Select the default BOM structure.
Select the Base Quantity: Choose Each or one of the parameter options.. If you choose User Parameters, in the Base Quantity box, select the parameter. If the user parameter does not exist, use the Edit parameters button to add the parameter and then select it. Click OK to accept the value. If not already specified, select a Base Unit from the list.
Note: The value you enter in the Base Quantity box can be appended by a unit. The unit is then automatically selected as the Base Unit.