Product Manufacturing Information (PMI, NX)
NX's MBD toolset — apply dimensions, tolerances, GD&T, and notes directly on the 3D model.
Definition
PMI (sometimes called GD&T in NX speak) applies dimensions, tolerances, datum references, surface finishes, and notes to 3D faces. Annotation views control visibility per orientation. Combined Views package camera + PMI visibility + section state for sheet-like display. PMI exports to 3D PDF, JT, and STEP AP242.
Why it matters
Model-Based Definition is increasingly required in aerospace, automotive, and medical supply chains. PMI is NX's implementation, mature and widely deployed.
Technical Deep Dive & Core Mechanics
In 2D vector engines like Siemens NX, Product Manufacturing Information (PMI, NX) directly influences the system's memory-mapped database structure. Rather than storing arbitrary pixel rasters, the DWG/DXF format describes each entity using grouped DXF codes (such as code 10 for coordinates, code 8 for layers, and code 100 for class markers). The virtual screen index utilizes highly optimized spatial indexing trees (like quad-trees or R-trees) to manage viewport pan and zoom sweeps efficiently.
Cross-Discipline Collaboration & Handoff
In global multi-office projects, Product Manufacturing Information (PMI, NX) is a high-frequency handoff node between diverse software packages. During cross-platform export (for example, exporting Siemens NX drawings to IFC for coordination in Navisworks or Solibri, or converting mechanical STEP files into BIM detail families):
Common pitfalls
- PMI on faces without datum reference frames — unenforceable tolerances.
- Mixing PMI with 2D drawings — duplicate spec definitions.
- Combined Views with stale geometry references after model edits.
This concept is a core structural element of the Siemens NX drafting and engineering environment developed by Siemens Digital Industries Software. Siemens' high-end CAD/CAM/CAE platform — synchronous + parametric hybrid modelling, strong CAM, and Teamcenter PLM integration.
Relevant Siemens NX FAQs
❓ What is the difference between NX and UG?
Same product, different name. UG (UniGraphics) is the legacy name from 1973 until 2002, when Siemens (then EDS) rebranded to NX. Veteran users still say 'UG.' The .prt file format is continuous across the rename — UG files can open in modern NX.
❓ What is Synchronous Technology and why does NX have it?
ST is direct-face editing on a body without disturbing parametric history. NX has it because it solves two pain points: editing imported geometry without history, and editing native parts when parametric edits would be tedious. Mixing ST with parametric is uniquely NX's capability.
❓ Does NX require Teamcenter?
Not technically — NX can run with the native filesystem. But production deployments almost always use Teamcenter (or NX X with Teamcenter X for cloud). Without it, large-assembly performance and revision control become unmanageable.
⚡ Concept Self-Test
🎓 Recommended Practice Lessons
Step-by-step practical exercises and certification-aligned paths chosen by our editors to master this concept:
The Complete Siemens NX 2026 Masterclass: From Beginner to Pro
Siemens NX Professional Design & Engineering Specialization
Siemens NX Certified Associate Exam Study Guide & Mock Practice
🌳 Semantic Crossroads & Navigation Pathways
Trunk-Branch-Leaf ModelCore glossary, interactive graph, and domain-wide concept index.
Parent design environments and platforms implementing this method natively.