Seven things you need to know about 3-D scanning
A white paper from Teaching and Learning with Technology at Penn State

At a glance

3-D scanning is the process by which a physical object is automatically turned into a digital 3-D model by a computer.

  • Several inexpensive consumer-level technologies are evaluated.
  • A useful tool for those without the technical ability to create print-ready 3-D models.
  • 3-D scanning and printing can increase student learning.

Who to contact

Maker Commons team, Teaching and Learning with Technology

Usage scenarios

3-D scanning of human cadavers: In recent years, there has been much debate about the cost and ethics involved in requiring medical students to complete research and learning exercises using human cadavers. One way to save money and reduce the need for human cadavers has been the use of 3-D scanning. At Monash University in Australia, 3-D scanning of human cadavers has been a method of reducing the cost, need, and ethical concerns of human cadaver donation for use in human anatomy courses.

3-D scanning and printing of fossils, rocks, and maps: Nick Schmerr, assistant professor of geology at the University of Maryland, and his colleagues Laurent Montési and Vedran Lekic started a crowdfunding campaign that ended on November 23, 2015. They completed their goal of collecting $7,000. They believe that 3-D scanning and printing of rocks, fossils, and geologic data will revolutionize teaching and research in the department. They envision 3-D scanning and printing of many different types of geology objects:

  • Dinosaur skeletons: Heavy and nearly impossible to put together, by printing lightweight plastic fossils at 1/10 the size, students can engineer fully working limbs to create a fully accurate robotic dinosaur leg or arm, and eventually, a complete dinosaur.
  • Touchable topography: Students can develop a sense of scale and visualize the connection between topography on a map and topography in the real world through 3-D topographical models that combine features like underground rock layers and the resulting surface patterns.
  • Rocks: The microscopic, intricate pore networks and exterior shape of rocks can be examined in scaled up 3-D printed models.
  • Crystal models: Representation of crystal shapes of minerals—such as a hexahedron, rhombohedron, octahedron, and dodecahedron—are common in geology classrooms. 3-D printed tactile models will allow students to see and “feel” the symmetry of these shapes.

Multidisciplinary student team creating a 3-D printed map for the visually impaired: 3-D scanning and printing brought together an interdisciplinary group of students at the University of Central Missouri to create a campus map for a student who is blind. Professor Jim Loch’s Introduction to Geology class includes a mapmaking assignment. He came up with an idea to modify his typical assignment due to having a student who is blind in his course. He brought together students from several majors to create the 3-D campus map. Teamwork was a major component of the project as well as learning to work with people who have very different skill sets. Included on the design team were CADD students, student Braille specialists, Accessibility Services staff, and a student who is a social work major. The end result will not just benefit the student but anyone with a visual impairment who visits the campus.

Methodology

3-D scanners were evaluated through a set of criteria identified to best relate to the types of scanning requests most likely to be encountered through academic use. This was done by first identifying the types of objects most likely to be scanned and categorizing them by their most significant feature set when evaluated through the lens of 3-D scanning. An object was then chosen to be representative of each category and each scanner was used to scan the objects.

The object categories to be scanned were:

  • Solid object with medium-level detailed features (small action figure used as representative object)
  • Object with negative space (coffee mug used as representative object)
  • Object with fine-level detailed features (multiple-sized gear assembly used as representative object)
  • Person

Criteria for evaluation applied to each category by scanner included:

  • Ease of use for scanner to scan object and produce model file
  • Duration of scan to produced model file
  • Physical limitations
  • Quality of produced model file (i.e., could you print this or does it need to be “cleaned up” in CAD software?)
  • File format compatibility with MakerBot 3-D printers

Results

Overall results point to different scanners being more or less useful for scanning different categories of objects. Of the scanners tested, we will be pursuing the use of the MakerBot Desktop Scanner and the Structure Sensor by Occipital.

The MakerBot Desktop Scanner performed adequately for capturing the medium-level detailed object. The object with negative space utilized the multiscan feature, which allows the user to scan the same object repeatedly from different angles with the software incorporating the various scans into a single model. The multiscan adequately captured the negative space found within the coffee mug, although the full depth of the negative space was not represented. The fine-detailed multiple-sized gear assembly was not captured well and the MakerBot Desktop Scanner’s physical limitations does not allow for a scan of a person.

The Structure Sensor by Occipital clearly favors larger objects. The small medium-level detailed object and fine-detailed object could not be properly rendered by the Structure, primarily due to their small size. The object with negative space ran into issues with detail on the exterior; however, the Structure was the best at understanding the negative space within the coffee mug and rendering it appropriately. The Structure was also very good for scanning a person’s body with only minor issues in unintentionally capturing the person’s surroundings as well (like the floor, for example).

Resources

MakerBot Desktop Scanner

Microsoft Kinect (using KScan3D)

123D Catch iOS app

Trnio iOS app

Structure Sensor

Research team

Ryan Wetzel, Teaching and Learning with Technology
Chris Stubbs, Teaching and Learning with Technology
Markus Furer, Teaching and Learning with Technology
Trace Brown, University Libraries
Julie Lang, Teaching and Learning with Technology
Tim Robinson, College of Earth and Mineral Sciences

1. What is it?

3-D printing has vast potential in the teaching and learning with technology landscape. However, participation in 3-D printing often requires a significant amount of technical knowledge. In order to print a 3-D object, you must first start with a model to print. Depending on your needs, you might be able to find a 3-D model on the Internet that suits your purpose, such as on Thingiverse, the free 3-D model sharing website run by MakerBot. However, if no such model exists, your only option is to create the object you wish to print.

Anyone who has ever tried to create a 3-D model knows that to do modeling well is a career. It takes considerable training, skill, and practice to create not only a model that looks like the object you are trying to create but also one that is designed to be printed. This is far too complicated for the majority of students and faculty who wish to benefit from 3-D printing.

3-D scanning, then, can become a useful and relatively simple tool for those without the ability to model in 3-D to create and, using simple software, modify print-ready 3-D models. Done successfully, this allows many users from the “mainstream” to engage with 3-D printing for teaching and learning.

3-D scanning is the process by which a physical object is automatically turned into a digital 3-D model by a computer. Scanning can happen in a number of ways. The purpose of this paper is to examine popular and relatively inexpensive ($800 or less) consumer-level technologies, determine parameters for a successful scan for each scanner, and make recommendations for their uses in the upcoming Maker Commons 3-D printing service provided by Penn State’s Teaching and Learning with Technology group.

The intention of using these scanners and creating 3-D models is to manufacture objects from the models using 3-D printers. Considerations for using scans to create 3-D models for other uses, such as in video games or virtual reality simulations, were not taken into account.

The following scanners were tested:

  • MakerBot Desktop Scanner: $799
  • 123D Catch iOS app: free
  • Trnio iOS app: free
  • Structure Sensor: $500

Ultimately, the audience for using these scanners in an academic context are students with potentially no previous experience using 3-D scanners or 3-D printers. Therefore, emphasis was placed on testing the scanners for:

  • ease of use
  • processing time
  • quality of scanned 3-D model
  • quality of resulting 3-D print (where applicable)

2. Who is using it?

Various levels of 3-D scanning technologies are being utilized today. The Smithsonian, for example, is using professional-level scanners to scan every inch of the space shuttle. Professors such as Mark Shriver of Penn State’s Department of Anthropology is using scanners to print and study faces. 3-D scanning is also becoming popular at the consumer level. The Microsoft Kinect, for example, can be used to scan your face into popular video games in order to create an avatar of yourself. Academically, the University of Michigan and the University of Florida both have 3-D design spaces that incorporate scanning technology.

3. How does it work?

There are two general types of 3-D scanning processes. In one method, lasers are used to scan an object or surface and then a high-resolution model is constructed based on timing or brightness differences that correspond with points on the object. The second method uses a series of photographs to construct the model. The laser methods use expensive devices and extensive computation to determine points within 3-D space. These are generally available to higher end manufacturing or government clients and were not explored in this study.

The more cost-effective, consumer method uses a series of digital photos to interpolate object edges for modeling. Combinations of external hardware devices and software running on an external computer are used to do this. The Makerbot Digitizer utilizes a type of hybrid scanning process that involves a laser to illuminate the object edge while it is rotated on a motorized turntable that is controlled by the MakerBot Digitizer software running on Mac OS X or Windows. Photos are taken by the device and then a visible light laser illuminated edge is used to construct a mathematical point cloud from the laser reflection that is a constant +45º from the camera for the first rotation and then -45º for the second rotation. The digitizing software does allow for additional rotations beyond the initial twelve-minute sequence to be used if additional detail needs to be captured and added into the modeling determination.

The Structure Sensor uses an infrared laser diode and camera that are built in to the device that is attached to an iPad which runs the control software. The iPad is moved around the object and a model is constructed from the collected data.

123Dcatch and Trnio are apps for iOS and Android devices that use the internal camera of the devices to take photos using natural light illumination, from which a model is derived using cloud computing services.

For our study, we have grouped these different methods of scanning objects into those involving external hardware devices (MakerBot Digitizer Desktop Scanner, Structure Sensor) and those employing software-only methods (123D Catch, Trnio).

Diagram showing that a MakerBot desktop scanner, Microsoft Kinect, 123D Catch I O S app, Trnio I O S app, structure sensor, and CAD can all be used to generate an S T L file which can result in a 3-D printed object.

Multiple methods of generating a stereolithography (STL) file used to produce a 3-D printed object

4. Why is it significant?

Despite the popularity of the “maker” movement, successfully leveraging tools like 3-D printers can require overcoming fairly significant barriers to entry, particularly in the creation of 3-D models themselves. While individuals in certain disciplines such as architecture, engineering, or graphic design may have experience in 3-D modeling, for the vast majority of people, creating virtual representations of objects is a daunting task, one which can deter otherwise interested “makers” from exploring 3-D printing.

3-D scanning technologies can help to reduce this burden by making it possible for anyone to create high-quality 3-D models of real-world objects, even individuals with little to no 3-D modeling experience. Even for experienced modelers, scanning tools can save significant amounts of time, allowing users to scan existing objects instead of taking hours or more to recreate them from scratch.

Ultimately, these tools are designed to make it easier and faster for anyone to create 3-D models.

5. What are the downsides?

Though 3-D scanning tools can be tremendously empowering, it is important to consider that as a relatively new genre of technology, they are not without several important drawbacks which can greatly inhibit their effectiveness. Arguably, the most important consideration generated by our analysis is that there is no “one size fits all” 3-D scanning technology. What scans a human being with great precision might struggle to accurately capture a coffee mug. And what works perfectly to scan a matte green mug may struggle to capture a glossy black mug. Each scanner seemed to have a specific type of object (in terms of size, finish, composition) which it was ideally suited to capture. This lack of flexibility among scanners can prove problematic if you want the ability to scan a wide variety of objects. but do not want to pay to purchase a variety of scanning tools.

Secondly, depending on the tool, object, and environmental conditions present during the scan, some scans may include “shrapnel”—bits and pieces of the environment that were unintentionally picked up during the scan. These extraneous objects require removal before most object scans can be used and this process can be time-consuming.

Finally, while scanning technologies are generally easy to use, some do prove more complicated (technically) to set up and may require calibration to work effectively.

Montage of 4 photos: a real mug, a structure scanned mug with portions missing, a digitizer scanned mug, and a digitizer printed mug.

Scan of a mug

Montage of 3 photos: real gears attached to a metal apparatus, structure scanned gears, and digitizer scanned gears.

Scan of gears

Montage of 4 photos: a real wind-up toy figure, a structure scanned figure with most portions missing, a digitizer scanned figure, and a printed figure.

Scan of a figure

Montage of 2 photos: Graham standing in the Pattee Library Media Commons, and structure scanned Graham with his feet missing.

caption: Scan of a person, Media Commons staff member Graham

6. What are the implications for teaching and learning?

Ways in which 3-D scanning and printing can increase student learning include the following.

  • Experimenting with innovation and problem solving at every step of the process provides an opportunity to practice iterative design skills. These are valuable skills, not just in enhancing the quality of learning, but also beneficial to students in their future careers.
  • Problem solving that requires students to practice creative and critical thinking. According to constructivist learning theory, these types of activities are highly valuable in student learning.
  • Providing students with the ability to create something concrete to help them learn an abstract concept, for example models in chemistry.
  • 3-D scanning projects are being used in higher education as a method of building collaboration and teamwork skills that students will need to as they move from the university to the career place.
  • Providing an opportunity for students to work in interdisciplinary teams to create something that has a real-world purpose.
  • Allowing students to make a difference in the lives of others who have physical or visual impairments.

The evaluation performed for this white paper indicates that faculty and students at Penn State do not have to understand all of the technical implications of using 3-D scanning. The criteria tested provide a guideline so that faculty and students only have to express interest in how they might scan any given object and Maker Commons consultants can point them towards the scanner that will be the best fit for their objective.

7. Where is it going?

Expectations are for 3-D scanning to improve drastically within the next five years. As the demand for consumer-level 3-D printing grows, so will the demand for 3-D scanning. This demand will generate increased research and development which should improve cost, ease of use, and reliability. It is highly likely that they largest immediate growth area will be in mobile applications, since these are both cost-efficient and easy to use. Mobile applications have the advantage of using existing devices, which would allow for more early adopters. Dedicated devices will likely improve as well and should provide better results than using apps on existing devices.

Today, consumer-level scanners are producing relatively poor scans and therefore have a limited use. Eventually, the quality will improve to a point where usage becomes more of an interesting discussion. We can already see the potential uses by institutions such as the Smithsonian. They are currently using sophisticated 3-D scanning equipment to create 3-D digital models of artifacts so that they can be preserved in their current state.

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