A phantom assembly is a node on the browser used to group components to simplify the design process. They exist in the design, but are not distinct line items in a bill of materials.
Phantom assembly nodes are indicated by the 
icon on the mechanical browser.
Typical examples of phantom assemblies include sets of hardware where the components are purchased and assembled separately, but are commonly used together (for example, screws, nuts, and washers).
Phantom assemblies have the following characteristics:
- They are ignored by the BOM.
- They are not numbered, and are not directly included in quantity calculations.
- They influence their children's participation in the BOM by promoting them in Structured BOM views. The children of a Phantom component is treated as siblings to the phantom component siblings, even though from a model structure standpoint this is not true.
- The quantity of their children is multiplied by the quantity of the phantom component.
Any local assembly can be set as a phantom assembly. External reference assemblies cannot be set as phantom assemblies.
It is also possible to set an assembly as a phantom assembly in the current drawing only. In this case, the assembly is a phantom in the current drawing, but continues to be a normal assembly in drawings that use it as an external reference (xref) component. It is convenient to set the top-level assembly of a drawing as a phantom in the current drawing. When you use the structured representation of the BOM, you save the extra step of having to expand the top level assembly, while none of the other files using this as an xref component are affected.