Define Component Population in a PCB 3D Export

A PCB model can represent the bare board, one assembly variant, or a larger component envelope. Each is useful for a different mechanical review. State which population the export represents before using the absence of a collision as evidence that an enclosure fits the production assembly.

Choose the intended mechanical question

For a particular shipping configuration, include the components actually fitted and any separately installed items needed for the review. For a shared enclosure across variants, a combined clearance envelope may be appropriate. Label that envelope clearly because it can contain components that never coexist on a real board.

KiCad 9’s command-line 3D export options include controls affecting DNP and component inclusion. Review the settings for the selected export format and version rather than assuming the interactive viewer and generated file share the same population.

Reconcile expected and visible bodies

• List the assembly revision and variant represented by the model.
• Identify components intentionally omitted from the export.
• Check model availability for every clearance-critical part.
• Open the exported file in the receiving mechanical application.
• Compare visible bodies with the expected component reference set.

A missing body can result from an intentional population filter or an unresolved model path. Those cases require different action. Use the portable-model-path check before classifying missing geometry as an assembly decision. Inspect components that contain several separate model files as well.

Keep a clearance result attached to its population

For example, variant A may omit a tall connector that variant B installs. An enclosure check performed with A’s exported model does not validate B. Conversely, a combined model containing mutually exclusive connectors may report a collision that no assembled product experiences. The review must identify whether it checks a real variant or a deliberately conservative envelope.

Perform the STEP clearance review with that population recorded. Include hardware, wires, mating parts, and required installation movements through the appropriate mechanical model or separate assessment; exporting the PCB alone does not automatically provide them.

Archive the mechanical file together with the population manifest and export settings. If a later BOM change makes a formerly DNP part populated, flag the mechanical review for reconsideration even when board dimensions and mounting holes remain unchanged. The meaning of a model changes when its fitted component set changes.