Structure of bills of materials

The BOM Structure property defines the status of the component in the BOM. BOM Structure has five basic options: Normal, Phantom, Reference, Purchased, and Inseparable.

The BOM Structure is by default set to the value defined on the Bill of Materials tab in Document Settings. You can override the structure to be Reference at the component instance level.

BOM Structure of Content Center library parts

By default, the BOM Structure is set to Purchased for all standard components. Custom components (components with a user-defined parameter) are set to Normal.

BOM Structure of iParts

All iPart components have a BOM Structure identical to the iPart Factory that generated them.

Normal

Normal is the default BOM Structure for most components.

Normal components have the following characteristics:

Phantom

Phantom components are used to simplify the design process. They exist in the design, but are not distinct line items in a bill of materials.

Examples of phantom components are:

Phantom components have the following characteristics:

Phantom Interaction with Normal, Inseparable, and Purchased Child Components

When a parent component is phantom, and it has children that are normal, purchased, or inseparable, then:

Note: If a parent component has the BOM Structure set to Normal, and all its children are phantom (or reference), then the parent is not displayed in a parts-only parts list.

Reference

Reference Components are components that are used for construction geometry or add context to a design.

Examples of Reference Components are:

Reference components have the following characteristics:
  • They are ignored in the BOM.
  • They are excluded from the mass calculations.
  • They are not numbered, and are not directly included in quantity calculations.
  • Child components of the reference component are ignored in the BOM.
  • They are shown with a hidden line style in drawing views.
Note: Use View Representations to control the display of reference components in the assembly and in drawing views. The display of reference components in drawing views is controlled in the Model State tab of the Drawing View dialog box.

When a component has a BOM Structure of Reference, the BOM treats the component and all its direct and indirect children as if they do not exist. All components, that are a part of a Reference component, are excluded from quantity, mass, or volume calculations, regardless of their own BOM Structure value. Reference components also have special treatment in drawing views.

Purchased

Purchased components are components that are not fabricated.

Examples of Purchased Assemblies include:

Purchased components have the following characteristics:

Inseparable

Inseparable components are generally assemblies where a component or multiple components must be physically damaged to disassemble the assembly. Many manufacturing processes consider inseparable assemblies to be a single line item like purchased components, but Inseparable assemblies are fabricated, not purchased.

Examples of inseparable assemblies are:

Inseparable components have the following characteristics:

Inseparable assembly with purchased children components

Inseparable components and purchased components have one difference in their behavior. In a parts-only parts list or BOM, all children of a purchased assembly are hidden. The assembly itself shows up as a line item in the BOM. For Inseparable assemblies, child components with a BOM structure of normal or inseparable are hidden. Purchased child components that are inside an inseparable assembly are still displayed in the parts-only parts List.