How to Preserve Historic Architecture

Digital Documentation
How to Ensure Your Historic Site is Preserved for Generations

By Steve Gordon

This brief text highlights the key points made in my recent talk on digital documentation for historic and heritage sites. You will also find links to websites referred to in the presentation.

The Importance of Architecture

Architecture is the art we live in. It is the most interactive form of art, and the most reflective of us as human beings.

"The mother art is architecture. Without an architecture of our own we have no soul of our own civilization"
-- Frank Lloyd Wright

Our architecture communicates the power and nobility of our institutions. It describes our daily lives. It tells the story of where we were and where we are.

"Design is the fundamental soul of a man made creation."
-- Steve Jobs

The Threat to Our History

Our history is threatened. As I write this in May, 2009, hundreds of historic structures in northern Italy lay in ruins. The result of a 6.3 magnitude earthquake in the Abruzzo region of central Italy (less than 100 miles east of Rome). The humanitarian loss is great and, of course tragic. And the architectural loss is large. And this is just one event.

On September 13, 2008 historic buildings in Galveston, Texas were battered and flooded by Hurricane Ike as it came onshore. The historic structure now occupied by the Galveston Arts Center filled with six feet of water, ruining everything on the first floor...including the walls.

In 2001, the Taliban blew-up the Bamiyan Buddhas in Afghanistan.

Beijing's Forbidden City is shrouded in smog most days. The pollution eats away at the building in this ancient site, while urban development surrounds the site on all sides.

And as you read this the the entire city of Venice, Italy is sinking. One of the most unique examples of human design, this "floating city" is battling on two fronts. First, the land under the city is sinking. Second, the seas that surround it are rising as a result of climate change. Over the last two-hundred years the water mark on city buildings rose 31 inches. Over the next 90, the water is predicted to rise 35 inches more.

Natural disasters, polution, climate change, human development, even terrorism threaten humanity's historic sites.

What can we do?

The Challenge: Capture and Preserve

If our historic sites are disappearing or being damaged by things beyond our control--earthquakes, hurricanes, terrorists--we need a method to capture the architectural forms. The designs. We need a way to preserve these sites digitally as insurance against destruction.

Once a site is digitally preserved, it can be studied, appreciated, even rebuilt in exact detail if the unthinkable ever happens.

What about photos? Photos are great. They do a good job of capturing the characteristics of an historic site. They're cheap (almost free with digital cameras). And photos have been proven to last over 100 years. Photographs are a great way to capture and digitally document your site. But they have some limitations.

First, they only capture what the photographer thought was important. In his or her limited field of view, each sot only shows a small piece of a historic structure. You need hundreds of photos to capture an entire site.

Second, photographs are two-dimensional. They flatten your three-dimensional structure, to fit a 2D format. Much of the experience of a historic space is the "space" itself. The relationship among rooms, the size, the scale, the texture. All of this information is lost in a photograph. And the experience is diminished.

"I have an idea...let's use a laser..."

A laser...that's crazy (or is it?). A new technology exists and is changing the way we document historic sites. The technology is 3D Laser Scanning (sometimes called High-Definition Surveying or HDS).The technology has been around for over a decade, but has been developed to the point that it is economical to use.

How it Works (just a few techie details). The Laser Scanner is a survey instrument. It shoots a laser beam from the instrument. The beam hits a wall or tree or column...whatever is in it's path...and is reflected back to the instrument. The instrument measures the time it took the beam to travel out to the object and back to the instrument. Using the physics of light, the instrument calculates the distance to the object using the time it measured and the speed of light. It repeats this about 25-million times each hour. In a very short time, you have a complete 3D model of your historic site.

Why a laser? Here are the top five reasons.

5. It measures every detail to millimeter accuracy.

4. You get a complete digital copy of your site's historic architecture (full 360 degrees--even overhead).

3. Your site is presented in 3D. You can walk through it "virtually.."

2. It's fast. Today's laser scanners are capable of capturing 25 million data points per hour. A historic house (smaller than a mansion) could be captured inside and out in two days.

1. Lasers are cool.

Important Laser Scanner Terminology

Point Cloud. A point cloud is what we call the collection of data points that make up the 3D scan of your site. As a cloud in the sky is made up of tiny water drops, that together look like a single solid object, a point cloud is made up of millions of tiny data points. Together, they form a 3D model of your site. Point clouds are the raw information produced by the laser scanner.

3D Rendering. A 3D rendering is a computer generated world that looks like the real world. In movies today, you can hardly tell what's real and what's been computer rendered. Architects often use 3D renderings to communicate what a new building will look like when it's built. Creating 3D renderings of existing, historic buildings has been expensive and difficult. Now with 3D Laser Scanning, it is much easier and less expensive to create renderings of existing structures using the point cloud data from the scanner as a starting point. 3D renderings look more polished than point clouds.

An Order of Magnitude or Two

When 3D Laser Scanning technology was invented by Ben Kacyra, his goal was to deliver an order of magnitude jump in speed and productivity. As a nuclear engineer he had reason to aim for this. It meant his people would spend less time taking measurements in dangerous places inside nuclear plants.

In surveying the state of the art measurement technology has been GPS (the Global Positioning System). Since the mid-1990's GPS has allowed us to make 300 to 500 measurements per hour. A three-fold jump from the previous technology. But laser scanning is on a different level all together. Ben achieved his goal, and it gets extended every year. Today's scanners are capable of making over 25 million measurements per hour.

Now we can collect every millimeter of detail...leaving nothing out...in less time than it took to get just the basic footprint outline of a building a few years ago. Such a huge leap in productivity brings the cost of full 3D digital documentation within reach.

Where Can Laser Scanning Be Used?

Laser scanning works equally well on small sites and large sites. The technology is compact and can travel to remote sites easily. It requires just one operator, and even carries it's own power when needed.

It works inside and outside, capturing the details of colonial millwork around a fire place mantle and the art deco styles of a Miami street scape.

Documentation: Fly-thru's, Elevations and Sections

With your site scan complete, you can now produce any type of documentation you need. Common deliverables include 3D "fly-thru" videos of your site, like a digital walking tour. Architectural drawings like elevations and sections to show exact the dimensions of your building. 3D renderings that create movie-like virtual experiences for your patrons.

Laser Scanning gives you the ability to invest a little now, to scan your site. Once scanned, it's preserved. You may never need fly-thru's or architectural drawings, but you can always get them if you do. By scanning now and processing the information later, you can have the peace of mind of full documentation, without the expense of creating a catalog of documents you don't need right now.