Direct Edit (NX)
NX's set of direct-modelling operations — Resize Body, Resize Face, Modify with Rules, Replace Face, on geometry without history.
Definition
Direct Edit operates on imported geometry (STEP, Parasolid, IGES imports without history) or on native bodies where history-based edits are inconvenient. Common operations: Resize Body, Resize Face, Modify with Rules, Replace Face, Delete Face. These edits add to the feature history as 'modify' steps that don't replay parametrically.
Why it matters
Imported geometry without history can only be edited via Direct Edit (or full re-modelling). For native geometry, Direct Edit short-circuits complex parametric edits when expediency matters.
Technical Deep Dive & Core Mechanics
In 2D vector engines like Siemens NX, Direct Edit (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, Direct Edit (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
- Heavy Direct Edit on native parts — feature history no longer represents the design.
- Direct Edit results that should have been parametric edits — lost design intent.
- Forgetting that Direct Edit doesn't propagate to downstream Synchronous features.
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 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.
❓ Can NX open SOLIDWORKS files?
❓ Can NX do BIM?
Not directly. NX is mechanical / aerospace-focused. For BIM (building information modelling), Siemens has Bentley products via partnership, but NX is not the BIM tool. For plant 3D design (process plants), NX is also not the typical choice — Comos or AVEVA / Bentley handle plant.
⚡ Concept Self-Test
🎓 Recommended Practice Lessons
Step-by-step practical exercises and certification-aligned paths chosen by our editors to master this concept:
Siemens NX Certified Associate Exam Study Guide & Mock Practice
Siemens NX Professional Design & Engineering Specialization
The Complete Siemens NX 2026 Masterclass: From Beginner to Pro
🌳 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.