🎯 Lesson: Types of 3D Scanners

🧠 Focus: Explore the various types of 3D scanners, how they work, and their ideal use cases in the world of digital fabrication and reverse engineering.

✅ Lesson Summary

3D scanners are essential tools for capturing the shape and geometry of physical objects and converting them into digital 3D models. Depending on the scanning technology, different scanners offer varying levels of accuracy, speed, cost, and compatibility with different materials and environments. This lesson breaks down the most common types of 3D scanners used in professional, industrial, and consumer settings.

🎓 Learning Objectives

By the end of this lesson, students will be able to:

• Identify the main types of 3D scanning technologies

• Understand the working principles of each scanner type

• Recognize the strengths and limitations of each method

• Select appropriate scanner types for specific tasks or industries

• Compare desktop, handheld, and mobile scanning solutions

📘 Lesson Content

🟩 1. Laser Triangulation Scanners

How It Works
A laser beam is projected onto the surface of an object, and a sensor measures the reflected light at a known angle to calculate distance and geometry.
This method relies on triangulation to create a 3D point cloud.

Pros:

• High accuracy and resolution

• Suitable for small, detailed objects

• Fast data capture for surfaces

Cons:

• Sensitive to reflective or transparent materials

• Limited range; best for stationary scans

• Often expensive

Common Use Cases:

• Industrial part inspection

• Dentistry

• Jewelry and fine-detail modeling

🟨 2. Structured Light Scanners

How It Works
These scanners project a series of patterns (like stripes or grids) onto the object’s surface. Cameras record how these patterns deform over the object, which is used to reconstruct the shape in 3D.

Pros:

• High resolution

• Fast scanning time

• Great for capturing texture and color (RGB)

Cons:

• Sensitive to lighting conditions

• Difficulties with shiny or dark surfaces

• Not ideal for scanning outdoors

Common Use Cases:

• Human body scans

• 3D modeling for animation or gaming

• Orthotics and prosthetics design

🟥 3. Time-of-Flight (ToF) Scanners

How It Works
A laser emits a pulse and the scanner calculates how long it takes to return after bouncing off the object. Distance is determined by the time it takes for the light to travel back.

Pros:

• Can scan large areas

• Simple, robust system

• Good for architectural and large-scale scans

Cons:

• Lower resolution than triangulation or structured light

• Not ideal for fine-detail models

• Susceptible to accuracy loss over long distances

Common Use Cases:

• Construction and surveying

• Indoor mapping

• Large industrial asset scanning

🟦 4. Photogrammetry

How It Works
Takes multiple overlapping photographs of an object from various angles and uses software to generate a 3D mesh by identifying common points across images.

Pros:

• Inexpensive (uses standard cameras)

• Highly detailed with good lighting and resolution

• No need for specialized hardware

Cons:

• Time-consuming processing

• Requires consistent lighting

• Difficult with reflective or transparent objects

Common Use Cases:

• Archaeology and heritage preservation

• Game and film asset creation

• Outdoor terrain capture

🟧 5. Contact/Touch Probing Scanners

How It Works
Uses a probe that physically touches the surface of the object to record a point in space. Often part of a coordinate measuring machine (CMM).

Pros:

• Extremely accurate

• Works on shiny or transparent surfaces

• Not affected by lighting

Cons:

• Very slow

• Only captures surface geometry, not color

• Limited to rigid materials

Common Use Cases:

• Precision engineering

• Automotive and aerospace quality control

• Calibration and reverse engineering

🟪 6. Mobile/Infrared Depth Cameras (e.g., LiDAR on iPhones)

How It Works
Smartphones or tablets equipped with IR sensors or LiDAR modules emit infrared light and measure reflections to calculate depth maps.

Pros:

• Affordable and highly portable

• Great for quick scans and prototyping

• Growing ecosystem of apps and tools

Cons:

• Lower accuracy and detail than professional scanners

• Inconsistent results with shiny or tiny objects

• Best for general shape, not intricate detail

Common Use Cases:

• Indoor room mapping

• Quick prototyping

• AR/VR environment building

🧠 Summary

Each 3D scanner type has its strengths and weaknesses. Choosing the right one depends on your application, budget, and required detail. Here’s a quick recap:

📂 Optional Activities

Assignment:

1. Choose one scanner type you would use for:

   • A small figurine

   • A historical building

   • A car component

2. Justify your choice with 2–3 supporting reasons

3. Optional: Try a free photogrammetry app using your phone and upload the mesh

📎 Additional Resources

• 3D Scan Hub: Scanner Technology Comparison

• Artec 3D Guide: Structured Light vs. Laser

• Photogrammetry with Meshroom – Free Workflow

• Apple Developer: LiDAR Scanner Use Cases