Part Properties

The Properties button on the main toolbar — the tag icon, beside the gear — opens a floating window holding the part attributes of the document you have open: its Part Number, Revision, Description, Material, Density, Supplier, and the rest — and its Mass and Volume, computed from its geometry.

These are the same attributes an assembly's BOM shows in its part. columns. A part carries them on its own document, so they travel with it: annotate a bracket here, save it, insert it into an assembly, and the assembly's parts list already reads PN-1042. Editing the same field from the assembly's BOM writes it back to the part's file.

An assembly has exactly the same fields a part does: a sub-assembly inserted into a larger one is a single BOM line in its parent, so it needs a Part Number, a Revision and the rest too. Solving an assembly's mates keeps the attributes you gave it.

Every field, whatever the BOM shows

The window lists all the part fields, including the ones your BOM column configuration hides, in this order:

1. the part. columns your configuration lists, in that order — the ones you starred and the ones you did not;
2. the remaining built-in part fields;
3. any attribute already stored on the document that neither of those names — one written by an older configuration, an import, or the automation layer, so anything stored can be read and cleared.

A field the configuration adds that is not built in (part.Alloy_Temper) is a plain text field, as in the table. The column configuration is in the Assemblies tab of Settings.

Editing

The editors are the BOM table's own:

• text commits when you leave the field or press Enter, not on every keystroke;
• numbers (Density) are drag values and keep their numeric type in the saved file;
• choices (Part Type, Make/Buy, Unit of Measure, Lifecycle State) always offer a blank — entry, so a choice you set can be unset again.

Clearing a field removes it. An emptied text box or a — choice deletes the attribute rather than storing "", and the last attribute cleared takes the empty record with it — a document you annotated and then cleared saves exactly like one that was never annotated.

Mass, Volume and Density

Mass belongs to the part, never to one placement of it, and it is computed: the volume of the part's geometry times its density, shown read-only with its unit (g below 1 kg, kg above; volume in mm³ or cm³).

• Density is in g/cm³. Leave it blank and the Material gives it when it names a common material (steel 7.85, stainless 7.93, aluminium or 6061 2.70, brass 8.50, copper 8.96, titanium 4.43, ABS 1.04, PLA 1.24, nylon 1.14 and others); the field then shows that density. A typed Density wins over the Material's.
• With no density, Mass reads no density: set the part's Material or Density — there is no default density.
• A document with no geometry (a purchased or library part) has nothing to measure: its Mass is a number you type here, in kg.
• A body's own density on the Info window's Metadata tab overrides the part's for that body, for a part made of more than one material.

The BOM's Mass column, the Info window of any of the part's bodies, the BOM export and the automation commands all show this one number.

Each field is its own undo step. Quantity is not here and never will be: it is how many times an assembly places the part, so it is counted, never stored.

Automation

part_attributes_get and part_attribute_set work without the window open.