Flatten reference designators

Use Flatten reference designator for module components to convert hierarchical designators into simple designators in the 2D PCB. For example, MOD1:R1 becomes R101, or another sequential value. This makes designators easier to read on manufacturing files and the BOM.

What is flattening?

In designs with schematic modules, components get hierarchical designators from their module instance. A resistor R1 in module instance MOD1 appears as MOD1:R1 on the PCB. With multiple instances, you get MOD1:R1, MOD2:R1, and so on.

Flattening removes the prefix and assigns new numbers. After flattening, MOD1:R1 and MOD2:R1 might become R101 and R102, or other sequential values.

How flattening works

When you enable flattening:

1. Existing components are ordered by position on the 2D PCB, starting from the top-left corner of the board
2. Ordering goes left to right, then moves down to the next row
3. Each component gets a new designator based on its position
4. The original hierarchical designator is kept internally

Components added after you enable flattening get top-level designators. They do not follow the position-based ordering. Use Renumber Designators to put them back in order.

Enable flattening in Design Preferences on the Designators tab. The setting is saved in the PCB file. You can disable it at any time to restore hierarchical designators.

Bill of Materials

When flattening is enabled, the BOM uses flat designators. For example, instead of MOD1:R1, MOD2:R1, it might show R101, R102.

Best practices

• Flatten when finalizing: Enable flattening after component placement is complete. Flattening early can cause confusion when you move components later.
• Toggle as needed: Switch between flat and hierarchical views at any time. Disable flattening to trace a part back to its module instance.
• Clean up before manufacturing: After moving or adding components, use Renumber Designators to put them back in order.

Limitations

• Flattening applies only to the 2D PCB view. Schematic designators stay hierarchical.
• Flattening requires a synchronized design. The schematic must be present and consistent with the 2D PCB.
• Flat designators cannot be edited directly — use Renumber Designators instead.