Assemblies & Item Trees

An assembly in LOP is a parent item composed of child items. When an assembly is added to a load plan, all of its components are included automatically — you don't need to add each part separately.

Assemblies are most useful when you regularly ship items that always travel together as a unit: a machine with its mounting brackets, a pallet pre-loaded with a defined set of boxes, or a promotional kit with multiple product cartons.

When to Use Assemblies

Use an assembly when:

• Items are always shipped together as a physical unit or pre-packaged set
• The combined item occupies a predictable space that is worth defining once and reusing
• You want to enforce that all components end up in the same container when shipping multi-container loads
• Your warehouse picks items as a kit rather than individually

Do not use assemblies for arbitrary groupings of unrelated items. Use plan-level item groups or separation tags for those cases.

Creating an Assembly

1. Go to Item Library
2. Click + New Item
3. Fill in the top-level (parent) item properties — name, dimensions, weight (this should represent the total packaged assembly)
4. In the Assembly section, toggle This is an assembly
5. Click + Add Component
6. Search for an existing library item to add as a component
7. Set the quantity for this component within the assembly
8. Optionally mark the component as Optional — optional components are suggested but not required when adding the assembly to a plan
9. Repeat for all components
10. Click Save Item

Assembly Structure

Assemblies in LOP support a two-level tree:

Assembly (parent item)
├── Component A  (quantity: 4)
├── Component B  (quantity: 2, optional)
└── Component C  (quantity: 1)

Nested assemblies (assemblies within assemblies) are not currently supported. If you need deeper nesting, define the inner assembly's properties at the parent level.

Component Properties

For each component in an assembly, you can configure:

Same-Container Requirement

By default, when an assembly is placed in a multi-container plan, LOP treats the entire assembly as a single item occupying the parent's bounding box — all components are conceptually inside that envelope. The optimizer places the parent item, not the individual components.

If you want the optimizer to place each component individually while keeping them in the same container, enable Place components individually in the assembly settings. With this option:

• The optimizer places each component as a separate item
• All components are assigned the same container group tag
• The solver attempts to keep all grouped items in the same container

Adding Assemblies to Plans

Assemblies appear in the Item Library alongside regular items. When you add an assembly to a plan:

1. In the editor's Items Panel, click Add from Library
2. Find the assembly (assemblies are marked with a tree icon)
3. Click to add

If the assembly has optional components, a dialog appears listing all components with checkboxes. Uncheck any components you want to exclude for this specific plan. Mandatory components cannot be deselected.

The quantity field lets you add multiple instances of the assembly at once (e.g., 4 units of the same machine kit).

Editing Assemblies

You can edit an assembly's components at any time from the Item Library:

1. Open the assembly item
2. Click Edit
3. Add, remove, or change quantities of components
4. Save

As with all library item edits, changes do not propagate to existing plans automatically.

Assembly Dimensions and Weight

The parent item's dimensions and weight define how the assembly is treated in the optimizer. Make sure these are accurate:

• Dimensions should be the outer envelope of the packaged assembly (the space it physically occupies in the container)
• Weight should be the total weight of all components plus any packaging material
• If components are placed individually, each component uses its own dimensions and weight

A common mistake is setting the parent weight to a single component's weight rather than the total. This causes inaccurate weight balance calculations in the load plan.