Three Dimensional artifact modeling, preservation and reproduction

By Mark Ciotola

First published on August 24, 2019. Last updated on February 6, 2021.

Objectives

Students will learn how 3D scanning and printing can act as a means of historical artifact preservation and reproduction.

Introduction

In the ancient times, the only way to reproduce a document was to rewrite it by hand. Then the printing press was invented, first in Asia then in Europe, that allowed a document to be reproduced many times. However, traditional printing requires plates to be made with the document content. Those planes might be carved in stone or wood, etched in metal, or made of individual characters of type, but in all cases, significant effort was required. For one or a few copies, reproduction by writing was often the fastest and easiest, even for entire books. In modern times, the photocopier was invented which allowed easy and routine reproduction of single or a few copies of documents.

However, until recently, reproducing single copies of three-dimensional objects (which we will also call artifacts) remained a largely manual affair, even where tools were used. However, 2-D printers began to incorporate digital technology. So instead of operating at the character level, printers were able to operate at much smaller resolutions, literally at the dot or “pixel” level. Modern printers can print at resolutions of hundreds of pixels per inch, suitable for many types of characters and even photographs.

If a digital printer can print photographs in two dimensions, why can’t it print in 3 dimensions? In theory, it can, but in practice, a different sort of machine is required.

The Technology

Scanning

Special software can take scans or photos of physical objects and stitch the images together into a three-dimensional object. Often this approach produces sufficient qualities, but sometimes it can produces irregularities. For better precision, a three-dimensional scanner should be used, or place the object on a turntable to ensure more consistent positioning.

3D scanning used for research and preservation at the Smithsonian Institute:

CAD Software

For cases where the object is hypothetical or is not physically available, an object can be designed in drawing software called Computer-Aided Design (CAD). Autodesk offers a popular CAD suite. It is expensive and run better on expensive hardware. However, Autodesk offers a suite of free applications as well.

Tinkercad is a free, cloud-based CAD program. It is not very precise, but it is sufficient to design simpler objects.

Printing

3D printing can either create a physical object from a digital design file or from scans and photographs of pre-existing physical objects. 3D printers print objects one “slice” or layer at a time, usually beginning at the bottom and building upwards. Most common 3D printers print in plastic which can be easily melted and channeled, but other materials can be used such as metals, resins, gypsum and even chocolate, but not on the same printer!

Printer and Material Types

3D objects can be printed in a variety of different material. The print material does not have to be the same as the original artifact material. For example, an ancient silver coin can be printed in bright orange plastic. Nevertheless, similarity in look and feel is often desired.

The most popular print material is plastic, which can be melted at a relatively low temperature and is usually non-toxic. There are not many older historical artifacts whose original material was plastic. However, plastics come in many different colors, so it is possible to print objects that are similar in appearance (or at least color) to historical objects. Plastics printers can cost as little as a few hundred US dollars, but are more typically several hundred dollars. Common plastics include:

ABS is the most common print material. It is a tough material and relatively strong.
PLA (polylactic acid) is biodegradable and is made of renewable materials such as corn starch.

Gypsum printers use powdered white gypsum that can be dyed to make complex blends and gradients of colors. The end product resembled lightweight rock, so it is good for printing models of bones, skulls and pottery. The output is somewhat grainy in texture. Gypsum printers cost tens of thousands of US dollars, so they are less common than plastics printers.

Resin printers can produce high resolution and precision prints that have much smoother surfaces. They are good for high fidelity prints and can even be used to produce medical test chips. Resin printers can cost around a hundred thousand US dollars.

Metal printers use a process called sintering to produce metal prints. These printers operate at relatively high temperatures and can be dangerous. They are only found in advanced printing facilities or specialty workshops.

Counterfeiting and Other Legal Considerations

There are several legal considerations involved when making copies of objects (or of even two-dimensional items). It should be obvious that it is unethical and often illegal to pass off copies as the original object. When this involves modern currency and coinage, this is obvious: counterfeiting currency is an well-known crime. Counterfeiting modern coinage is illegal but less common, since the coins are often more expensive to make than their face value. Jurisdiction matters. For example, it is illegal to make fake U.S. currency in the USA but apparently not in North Korea.

Making a copy that is different but resembles an existing object can involve further legal restrictions. If you distort an artistic copy without the artist’s permission, you may be violating a specific legal right called a Moral Right which is enforced in California and parts of Europe but not in most of the USA.

Ironically, in some jurisdictions, possession of a copy might be legal where of the original might be illegal. For example, some European and middle-eastern countries prohibit the possession of ancient coins, while they allow possession of reproductions.

Other items might be patented or copyrighted (documents, paintings, sculptures, household objects). Patents generally don’t last more than a few decades, but copyrights can last over 100 years. Some business, organization and government logos might have perpetual protection. Some copying can be performed in the USA under the “Fair Use” doctrine, but not all countries have this doctrine. Some governments have other types of laws that might cover certain areas, such as religious or cultural objects.

Resources

Tinkercad free online CAD software

Digital History