Stackable & Fragile
The Stackable and Fragile properties control how items interact with each other vertically in a load plan. Setting these correctly ensures the optimizer protects delicate cargo and respects structural limits.
Stackable
What it means: When an item is marked as stackable (the default), other items are allowed to be placed on top of it. When stackable is turned off, the optimizer will never place anything above this item.
When to use it:
- Turn stackable off for items that cannot bear weight from above — hollow containers, irregularly shaped items, items with fragile top surfaces
- Leave stackable on (default) for standard cargo like cartons, drums, crates, and pallets
Stackable = off is a hard constraint. The optimizer strictly enforces this — no item will ever be placed on top of a non-stackable item, regardless of how much space is available above it. This may reduce overall container utilization if many items are marked non-stackable.
Fragile
What it means: When an item is marked as fragile, the optimizer will not place any other item on top of it. Fragile items are placed on the top layers of the load, protected from crushing.
When to use it:
- Glass, ceramics, or delicate electronics
- Thin-walled packaging that cannot bear any load
- Any cargo where pressure from above could cause damage
Stackable vs. Fragile
Both properties prevent items from being placed on top, but they serve different purposes:
| Property | Can have items on top? | Placed where? |
|---|---|---|
| Stackable = off | No | Anywhere (floor or on top of other items) |
| Fragile = on | No | Preferably on top layers |
| Both set | No | On top layers |
Stackable is about structural capability — "this item cannot support weight." Fragile is about protection — "this item could be damaged by weight."
In practice, the result is similar. Use Fragile when the item itself is delicate. Use Stackable = off when the item is sturdy but has a surface that should not be loaded.
Max Weight on Top
For items that can support some weight but not unlimited stacking, use the Max Weight on Top field instead of turning stackable off entirely. This sets a hard limit (in kg) on the cumulative weight that may be placed above the item.
For example, a corrugated carton rated for 200 kg stacking load: leave Stackable on, and set Max Weight on Top to 200.
How to Set These Properties
In the Editor
- Select an item in the 3D viewport or click it in the Items Panel
- The detail panel on the right shows the item's properties
- Toggle Stackable or Fragile, or enter a Max Weight on Top value
- Changes are saved automatically
In the Item Library
- Go to the Item Library page
- Click an item to open its edit dialog
- Set Stackable, Fragile, and Max Weight on Top
- Save — these properties will apply to all future plans using this library item
Via Excel/CSV Import
Include columns in your spreadsheet:
- Stackable — accepts
1/0,yes/no,true/false - Fragile — accepts
1/0,yes/no,true/false - Max Weight on Top — numeric value in kg or lbs
LOP recognizes these column names automatically during import. With AI Smart Detection enabled, the columns are mapped with confidence scores.
Library Sync
When you update Stackable, Fragile, or Max Weight on Top in the Item Library, plans that already use that item will show an amber "⚠ Updated" badge. Click the badge to pull the latest properties into your plan.
This ensures that constraint changes made in the library are reflected in existing plans without having to manually re-enter values.
Next Steps
- Item Properties — full reference for all item properties
- Constraints & Rules — how stackable and fragile interact with other constraints
- Importing from Excel or CSV — setting properties during import