Organizational Approaches and Common Defects in PMI Reviews within MBD Environments

Redefining the Subject of Review

In 2D workflows, the review target is drawings. In MBD workflows, it's a combination of "model + annotations + view state." Since the same geometry can display different annotation sets depending on the view state, reviews must be bound to specific view states rather than reviewing the model generically.

This means review records must include the model version, annotation set ID, and a snapshot of the view state; otherwise, the review conclusions cannot be reproduced later.

Common PMI Defects

• Incomplete datum system: missing datums or datum sequence mismatched with process route.
• Redundant or conflicting tolerance annotations: the same feature is dimensioned in multiple locations with inconsistent values.
• Annotation does not match view direction: dimension projection direction differs from machining measurement direction.
• Surface finish requirements are missing or only shown on 2D drawings, with no corresponding annotations in the model.
• Semantic annotations are flattened to geometric text, preventing the receiver from automatically reading tolerance information.

Review Process Suggestions

• 1Pre-review: Freeze model version, export annotation list and view state list.
• 2In Review: Check in the order of "Baseline System → Tolerance Integrity → Measurability → Process Consistency," and record conclusions for each item.
• 3Post-review: Generate a defect list with assigned owners. After model modifications, rebind the version and re-review to avoid verbal confirmations.