Inventory items with an underbar, example _1x4 or _19 x 89, are called Placeholders. '_Placeholders' are a nonexistent Piece that's used to reserve the area that a piece would use if it existed.'
For example, when the Top Panel rests on a Side Upper Horizontal Framing Cleat but there's some reason you don't want to cut/process/attach that one cleat, HOWEVER, to determine the size and placement of other Pieces may be dependant on the dimensions of that piece being there. You can select a Placeholder item for that Piece.
For every material in Inventory, you have the option to check the Placeholder box which will add an additional Placeholder item for selection in the Design. A Placeholder will be available when designing a crate regardless if the Item is Active or Not. The Active and Placeholder checkboxes are independent.
When used, the Placeholder is independent of the 'real' item, so '_1x4' and '1x4' will always appear as separate items
(In DES there is a Dun(nage) checkbox associated with various Piece fields that use Lumber, . This is to indicate the piece has different reporting requirements under ISPM 15.
Dunnage Pieces will also be on a seperate line from other ISPM 25 tracked Lumber. A Placeholder cannot be Dunnage because the actual lumber usage reported must also be physically consumed from Inventory.)
A Placeholder will reserve the area that the 'real' item would fill but it doesn't affect Weight, Times, or Prices.
They will appear in the DES > Details > Pieces tab and on printed Cutlists. In addition to beginning with an _underline, the ItemID and Quantities will appear with a strikeout font style as a clear indicator that they are not real and are not to be cut. Also, if they were left off the Cutlists, shop employees could assume there was just a mistake, and they can easily 'fix' it.
DES > Packing > Other
Real Items that are added here don't have any particular placement on/in the crate but they can be indicated as associated with a particular Panel.
Material Weight, Times, and Cost of real Items are included in the Design totals however, the Waste Factor is not included in the calculation.
If an Item is used in a Design Piece field and is also used in Packing > Other then the Item in Packing > Other will use the same Waste Factor.
See the note at the bottom of the DES > Packing > Other layout.
(The idea here is that when someone has to think about the amount of a material required (strapping, wrapping, fasteners, etc) they'll know how many they want, and wouldn't want to reverse the Waste Factor in INV to rethink the qty they want. When something is already used in the Design (typically wood and foam), then the assumption is that it has to be processed in the same way as the other Pieces, and this will result in waste. Neither thought is perfect but seems most accurate and fairly simple.)
A Placeholder that's added in Packing > Other is the same as one added in a Piece field. It doesn't affect Weighs, Times, or Prices, and it also doesn't reserve any particular area since Packing > Other Items don't have a specific area so...
Fasteners are an exception. In INV > Fasteners there are two Time fields; Time (to install a fastener) and Fastener Prep Time. Some fasteners require preparation such as Lag Bolts which require a hole to be predrilled. An HPI may be supplied to the customer as KD/Knocked-Down so the customer can load it and close it. The crater would drill all the holes for the lag bolts but then the customer would install them. If the Design includes a Closure Fastener that has a PrepTime then the Time for that fastener would be (Time + PrepTime) * QtyOfUnits. But if you change the Closure Condition to KD / Knocked-Down, then the Time calc would be PrepTime * QtyOfUnits. This feature is very rigid and useful but also falls short of real-world needs.
A Fastener can be added in Packing > Other as a Placeholder. As with other Items, the INV Time won't be used, however, if the Fastener has a PrepTime, the PrepTime will be included. This allows the user to add any number of Fastener PrepTimes that he wants. No other values are associated with any Placeholders in Packing > Other.