Organizing PMI Reviews in an MBD Environment and Common Defects

Redefining the review object

In a 2D process, the review object is the drawing; in MBD, it is the combination of the model, annotations, and view states. The same geometry can have different annotation sets under different view states, so reviews must bind to a specific view state rather than "the model" as a whole.

Review records must include the model version, annotation set identifier, and view-state snapshot; otherwise, conclusions cannot be reproduced later.

Common PMI defects

• Incomplete datum scheme: missing datum features or inconsistent datum order relative to the process route.
• Conflicting tolerances: the same feature is annotated in multiple locations with different values.
• Annotation view mismatch: dimension projection direction differs from machining or inspection direction.
• Surface texture requirements are missing, or present only on 2D drawings without model annotations.
• Semantic annotations are flattened into geometric text, preventing the receiver from automatically reading tolerance data.

Recommended review flow

• 1Before review: freeze the model version, export the annotation list and view state list.
• 2During review: verify the order datum scheme, tolerance completeness, measurability, and process consistency; record each conclusion.
• 3After review: generate a defect list with owners; re-bind the version following model changes and re-review instead of confirming verbally.