Student Material 001: 3D Scanning Technology Quick Reference Guide

Material ID: U11M1-MAT-001 Purpose: Quick reference for 3D scanning technologies, specifications, and troubleshooting

Scanning Technology Comparison Chart

Feature	Structured Light	Laser Triangulation	Photogrammetry
Principle	Pattern projection + camera triangulation	Laser line + camera triangulation	Multi-photo feature matching + bundle adjustment
Accuracy	0.01–0.1 mm	0.01–0.1 mm	0.1–1.0 mm
Resolution	0.02–0.5 mm	0.02–0.5 mm	Scene-dependent (0.1–2.0 mm)
Speed	Fast (area capture)	Moderate (line scan)	Slow (manual capture + heavy processing)
Working Range	100–1000 mm	50 mm–several meters	No limit (camera-dependent)
Color/Texture	Yes (with color camera)	Limited	Excellent (from photographs)
Equipment Cost	$500–$50,000	$1,000–$100,000	Camera + software ($0–$5,000)
Ambient Light Sensitivity	High (interferes with patterns)	Low (laser wavelength filter)	Moderate (needs consistent lighting)
Best For	Lab scanning, organic shapes, medium parts	Industrial inspection, edges, long range	Large objects, outdoor, texture documentation
Struggles With	Reflective, transparent, dark surfaces	Slow for full-surface capture	Featureless, glossy, transparent surfaces

Scanner Specification Glossary

Term	Definition	Typical Values
Accuracy	Closeness of measurement to true value	±0.01 to ±1.0 mm
Resolution	Smallest distinguishable feature / point spacing	0.02–2.0 mm
Repeatability	Variation between repeated scans	±0.005–0.05 mm
Working volume	Capturable 3D space in one setup	100x100x100 to 1000x1000x1000 mm
Working distance	Optimal scanner-to-object distance	100–2000 mm
Field of view (FOV)	Angular or linear extent of capture area	50x50 to 500x500 mm
Point density	Number of points per unit area	10–500 points/mm²
Scan time	Time for one capture frame	0.5–10 seconds
Volumetric accuracy	Accuracy across entire working volume	±0.02–0.2 mm

Common Scanning Artifacts — Visual Identification Guide

Artifact	Appearance	Cause	Fix
Noise	Fuzzy, scattered points around surface	Sensor limits, ambient light, vibration	Average multiple scans; increase exposure time
Occlusion holes	Missing patches in point cloud	Surface hidden from scanner view	Scan from additional angles; reposition object
Reflectance artifacts	Bright spots, missing data on shiny areas	Specular reflection	Apply dulling spray or scanning powder
Edge noise	Exaggerated scatter at sharp edges	Pattern/laser ambiguity at transitions	Higher resolution; closer scanning distance
Registration error	Double-wall effect at scan boundaries	Poor alignment between scans	Re-align with better overlap; use reference targets
Motion blur	Smeared or distorted geometry	Movement during scan capture	Secure object; increase scan speed
Dark surface gaps	Missing data on black areas	Surface absorbs projected light	Scanning spray; increase projector brightness
Transparent surface gaps	Missing data through clear materials	Light passes through instead of reflecting	Opaque coating; alternative scanning method

Point Cloud File Format Reference

Format	Extension	Data Supported	Typical Use
PLY	.ply	XYZ, color, normals	General purpose; CloudCompare default
STL	.stl	Triangulated mesh (no color)	3D printing; CAD import
OBJ	.obj	Mesh + texture coordinates + materials	Visualization; texture-mapped models
PTS	.pts	XYZ + intensity	Large-scale / terrestrial scanning
E57	.e57	XYZ, color, intensity, images	Archival; interoperability standard
XYZ	.xyz / .txt	XYZ (plain text)	Simple interchange; any software
LAS/LAZ	.las / .laz	XYZ, classification, intensity	Geospatial / LiDAR data

Surface Preparation Quick Reference

Surface Type	Challenge	Solution
Shiny metal	Specular reflection	Dulling spray (AESUB, Attblime), baby powder
Black plastic	Light absorption	White scanning spray, increase exposure
Transparent (glass, acrylic)	Light passes through	Opaque spray coating; CT scanning
Very dark rubber	Low reflectance	Scanning spray; photogrammetry may work better
Highly textured	Shadows in crevices	Multi-angle lighting; multiple scan positions
Featureless white	No features for alignment/photogrammetry	Add reference targets; structured light preferred

Key Formulas and Relationships

• Triangulation angle: Larger baseline angle = better depth resolution but more occlusion
• Point cloud size: Points x bytes-per-point = file size (XYZ float32 = 12 bytes/point; +RGB = 15 bytes/point)
• Required scans: Object surface area / scanner field of view = minimum scan count (add 30% for overlap)
• Accuracy vs. distance: Accuracy typically degrades as working distance increases (check spec sheet curves)

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Last Updated: 2026-03-19