About the BOM Structure

The BOM Structure property defines the status of the component in the BOM. Define the default BOM structure values on the Bill of Materials tab in Document Settings. To change the BOM Structure, double-click the BOM Structure row in the Bill of Materials.

The BOM structure has five options:

Note: iAssemblies supports only the First-Level Structured view. The All-Levels Structured view or the Parts-Only view is not available.

Normal

Normal is the default BOM Structure for most components.

Normal components:

Phantom

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

Phantom components:

Examples:

Phantom Interaction with Normal, Inseparable, and Purchased Child Components

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

Note: If a parent component sets the BOM Structure to Normal, and all its children are phantom (or reference), 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.

Reference components:
  • are ignored in the BOM.
  • are excluded from mass and volume calculations.
  • are shown with a hidden line style in drawing views.
  • are not numbered and are not directly included in quantity calculations.
  • child components of the reference component are ignored in the BOM.

Examples:

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.

Purchased

Purchased components are components that are not fabricated.

Purchased components:

Examples:

Inseparable

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

Inseparable components:

Examples:

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 components are hidden. Purchased child components that are inside an inseparable assembly are still displayed in the parts-only parts List.

Virtual components

Use the Create In-Place Component command to create a virtual component in an assembly. A virtual component is a component that does not require geometry or a unique file. Virtual components are treated as real components. They have a browser entry, and have properties such as quantity and part number.

Examples:

  • Fasteners that you do not need to model.
  • Bulk items such as gas, paint, or lubricant.
  • Intangible bill of materials line items such as packaging or software.

If you delete all instances of a virtual part from the browser, the virtual component must be recreated using the Create In-Place Component command.

Tip: Create an assembly that contains your standard virtual components with the BOM properties defined. To save time, drag the required virtual components from this assembly to the new assembly.