Practical guide for engineers, product designers and manufacturing teams — by OTS

Hardware:  Handheld Laser 3D Scanners, Optical Dynamic Tracking Systems, Portable CMM Arms

Software:  Geomagic Design X, Polyworks Modeler, Siemens NX

Step-by-step process

1) Plan the scan

• Define the CAD model purpose: inspection, reproduction, redesign, FEA or tooling
• Choose scanning method and resolution based on feature size and surface finish  

2) Acquire the data (capture)

• Calibrate the scanner following manufacturer instructions
• Capture overlapping passes with ~30–60% overlap for robust registration
• Record environmental notes (temperature, vibration, lighting, surface coatings) — helpful later for traceability

3) Register and align scans into a single point cloud

• Use marker-based or feature-based registration to stitch multiple scans
• Apply coarse alignment (manual/feature-based) then refine with ICP (Iterative Closest Point)
• Maintain traceability: keep original raw scans and the registered point cloud separately

4) Clean the point cloud

• Remove obvious outliers and stray points (spline filters, radius-based outlier removal)
• Crop unnecessary data (table, fixtures, background)

5) Generate and repair the mesh

• Create a watertight mesh from the point cloud
• Repair holes and non-manifold edges
• Decimate the mesh strategically: reduce triangle count for performance but preserve curvature in high-detail areas

6) Identify and extract CAD features

• Split the mesh into logical regions: planes, cylinders, cones, fillets, freeform regions. Use curvature analysis and feature detection tools
• Document reference datums and feature origins

7) Rebuild a parametric CAD model

• Start in the target CAD system and set up the correct units and reference planes
• Create sketches and features from measured primitives. Use measured values as constraints rather than tracing the mesh directly
• Preserve design intent: wherever possible recreate features as parametric sketches/features (extrude, revolve, fillet) so the model remains editable

8) Validate the CAD model

• Perform a deviation analysis: compare CAD model to original scan and generate color maps showing deviation (commonly ± tolerance bands)
• Check critical GD&T dimensions and functional fits

9) Prepare final deliverables

• Export neutral formats: STEP for solids, IGES for surfaces, and native CAD files for editing. Provide mesh (.stl/.obj) if needed for additive manufacturing
• Include metadata: scan date, scanner model, scanning parameters, alignment method and validation reports (deviation maps, critical dimensions)
• Archive raw scans, registered point cloud, repaired mesh and final CAD model

Example Applications

• Re-creating discontinued parts for legacy equipment
• Reverse engineering tooling and jigs for faster iteration
• Preparing accurate CAD for FEA or CFD when original drawings are missing
• Converting as-built conditions to CAD for retrofit or retrofit design