Look, but Don't Touch18 Feb, 2010 By: Nancy Spurling Johnson
The fantasies of sci-fi become real as digital holograms bring virtually any 3D data to life.
Editor's note: This article was originally published in the Winter 2010 edition of Cadalyst magazine.
When Elvis was beamed onto the stage of "American Idol" in 2007 to sing a duet with Celine Dion, and when correspondent Jessica Yellin popped onto the New York City set of CNN on election night 2008 — even though she was on assignment in Chicago — holography created quite a stir. Although some debated whether those were true examples of the technology, there's no question they got our attention.
Today, holography is getting attention in the design world as well, as a striking new way to present a 3D model. With what is known as a digital hologram, you're able to walk around the model — whether it be a skyscraper in its downtown setting, a topographic map, or even a life-size concept car — and view it from every angle. The model you see is fully detailed and highly accurate — but if you reach out to touch it, your hand will slice through the air.
When people see a digital hologram for the first time, the reaction is, "What is it?" and "How did you do it?" says Jay Mezher, manager of design visualization in the Seattle office of Parsons Brinkerhoff. The firm has used the technology to create infrastructure models that show proposed designs of highways and tunnels, and even to create an urban scale hologram depicting the city of Seattle. "This has added another amazing tool to the virtual design and construction [VDC] approach we take with our projects," he says. "We're intrigued by the ability to display a three-dimensional hologram instead of a projected 2D image."
These 3D models that you cannot touch are created from virtually any 3D data, printed on a flat surface, and viewable when light strikes them at a certain angle. Digital holograms can be used as a permanent display, or tiles can be disassembled and compactly stored or easily transported to another location for review. They are being used for applications ranging from design showrooms to overseas military operations.
How It Works
In contrast to analog holograms, which are exact 1-to-1 reproductions of existing objects, digital holograms are completely scalable and based on 3D data such as CAD models, laser scans, or satellite imagery. They can be created from other digital data as well, such as video footage or a series of photographs. Based on proprietary technology using lasers, optics, and image processing, digital holograms are printed by machine, pixel by pixel, to create what is effectively a compilation of thousands of high-fidelity rendered still images.
At Zebra Imaging, a developer of digital hologram technology based in Austin, Texas, color and monochrome holograms are printed on photopolymer film, usually in two to three hours' machine time depending on a model's complexity. The film is applied to acrylic tiles for display and easy portability. The result is a hologram that has a wide viewing angle and a large depth volume that appears to extend above and below the display surface, and that is full parallax, meaning the 3D depiction is correct from every vantage point.
View Holographics, a provider of analog and digital holographic services in the United Kingdom, uses red, green, and blue lasers at specific frequencies to create full-color digital holograms. An image is created within a photographic holographic emulsion coated on a sheet of glass. A 1-square-meter hologram requires approximately 10 hours to print, plus a few more hours to develop.
In their finished form, digital holograms can be displayed vertically on a wall or a stand, or horizontally on a table or a floor. The 3D holographic effect comes to life in sunlight or when an artificial light shines on the surface at a specific angle. No special glasses are necessary.
Multiple people can view a digital hologram from all vantage points around a static display; the model
appears to change according to each viewer's perspective, or the display itself can rotate. Some digital holograms convey a single representation of a model. Others could show a building design with and without a roof cutaway, depending on the viewing angle, or the progression of a product redesign from old to new.
Short 3D animations can be made by running several holograms in succession. As another option, Zebra Imaging can create transparent overlays for holograms to display annotations, updates, or other data or to show existing project conditions juxtaposed with proposed alternatives. "We're motivated by the potential of the technology," says Mezher, a Zebra Imaging client. "The possibilities are endless."
3D digital holograms can facilitate design review and collaboration in much the same way as a physical prototype, as shown in this visualization. Image courtesy of Zebra Imaging.
Digital holography has been used extensively by military and law enforcement personnel to create 3D topographic maps and building plans for various types of applications, including situational awareness, event preparation, and training. Geospatial applications — for military use and urban planning — have been the core business for Zebra Imaging.
However, as 3D data becomes increasingly prevalent, so do the applications of digital holography. The entertainment industry is using digital holograms in advertising, and oil and gas producers have used them to support stakeholder decision making. More recently the architectural and manufacturing sectors have begun to use digital holograms to communicate design concepts as well as schematic and detail designs. In VDC and building information modeling (BIM), digital holograms can facilitate collaboration among architects, contractors, and clients early in the design phase of a project.
One Zebra Imaging customer has used holography to present proposed dormitory updates for student feedback; another has compared an existing airport baggage-handling system model with a proposed redesign. "We expect the AEC and product design application areas to grow very rapidly over the next 12–18 months," says Dave Perry, executive vice-president, commercial markets.
View Holographics and Zebra Imaging can create digital holograms from virtually any 3D data. At Zebra Imaging, the preferred file formats are OBJ, FBX, DWG, and DXF. The company has processed 3D data from CAD applications including Google SketchUp, CATIA, Rhinoceros, 3ds Max, Maya, Revit, and AutoCAD. It currently is developing plug-ins to provide a print capability directly from Revit, 3ds Max, Maya, Google SketchUp, and other applications through a secure online pipeline.
Mezher at Parsons Brinkerhoff says his group has printed holograms based on models built in AutoCAD, Revit, SketchUp, MicroStation, and 3ds Max. "But the final model was assembled in 3ds Max, where textures and lighting were added and then exported to the hologram printer." Simon Potter, a sales and marketing associate at View Holographics, states that when 3D holograms are printed from 3ds Max models, "The results are always excellent."
View Holographics can print digital holograms as large as 1 m x 1.2 m (or approximately 39" x 49") at a cost of approximately $2.80 to $3.80 per square inch.
At Zebra Imaging, holograms commonly range in size from 12" x 12" to 24" x 36" and cost $799 to $2,999 for color output. The company has produced digital holograms as large as a 6' x 18' life-size rendering of a Ford concept vehicle.
View Holographics is continually refining its holographic technology. Potter reports that the company's newest printer will produce holographic prints that are brighter, have better color, and provide a 120-degree viewing angle.
Zebra Imaging is putting the finishing touches on a new color hologram printer that will sell for $1 million — most likely to traditional customers in the military and defense space, as well as to service bureaus. "We expect to make an announcement of commercial availability in the very near future," Perry says.
Before long, digital holograms won't even require a printer. Zebra Imaging is developing a dynamic, all-digital holographic display with funding from the Defense Advanced Research Projects Agency (DARPA) for interactive applications. Initially targeted for advanced visualization applications in military, weather forecasting, oil and gas exploration, and medical imaging, the display will integrate with existing 3D software applications. Commercial launch is planned for 2010.
About the Author: Nancy Spurling Johnson
Autodesk Technical Evangelist Lynn Allen guides you through a different AutoCAD feature in every edition of her popular "Circles and Lines" tutorial series. For even more AutoCAD how-to, check out Lynn's quick tips in the Cadalyst Video Gallery. Subscribe to Cadalyst's free Tips & Tools Weekly e-newsletter and we'll notify you every time a new video tip is published. All exclusively from Cadalyst!