When you think of the word cave, you might think of a dark, hidden place, right? Not anymore. The CAVE™ and CAVE2™, developed by the Electronic Visualization Laboratory (EVL) at University of Illinois at Chicago (UIC), create a virtual environment, somewhat like the holodeck on “Star Trek,” which can be used for many types of research. CAVE is an acronym for CAVE Automatic Virtual Environment.

Fig. 1 – A simulation of human brain vasculature and cortical tissue is displayed in the CAVE2 Hybrid Reality Environment (Credit: Lance Long for EVL)

In 1992, a group of scientists at the UIC, supported by the National Science Foundation, created the original CAVE—a room-sized, advanced visualization solution combining highresolution, stereoscopic projection and 3D computer graphics rear-projected onto the walls and down-projected onto the floor to create a sense of presence in a virtual environment.

The CAVE virtual reality system allowed multiple users to become fully immersed in the same virtual environment at the same time. The user wears 3D glasses inside the CAVE to see 3D graphics generated by the CAVE at approximately one million pixels per wall. Users can see objects apparently floating in the air, and walk around them, getting a proper view of what they would look like in reality. This was initially made possible by electromagnetic sensors, but has since been converted to infrared cameras.

Since then, the EVL has created CAVE2, the next-generation virtual-reality environment, a hybrid system that combines the benefits of both scalable-resolution display walls and virtualreality systems to create a seamless 2D/3D environment that supports both information-rich analysis as well as virtual-reality simulation exploration at a resolution matching human visual acuity. CAVE2 creates new opportunities for users to collaborate using both 2D and 3D.

How It Works

While CAVE used four projectors to display 3D images, CAVE2, which debuted in October 2012, uses 72 3D, LCD panels. The new system has three times more cubic feet of virtual environment, 66 times more brightness, 4,176 times more processing power, and 22,500 times the storage capacity. CAVE2 provides a near-seamless, 320 degree, panoramic 2D/3D environment that supports information-rich analysis with immersive visuals. CAVE2 supports both information-rich analysis and virtual-reality simulation at a resolution matching the range of human visual acuity.

CAVE2 is approximately 24 feet in diameter and 8 feet tall, and consists of 72 near-seamless passive stereo off-axis-optimized 3D LCD panels, a 36-node high-performance computer cluster, a 20-speaker surround audio system, a 10-camera optical tracking system and a 100-Gigabit/second connection to the outside world. It provides users with a 320-degree panoramic environment for displaying information at 37 Megapixels in 3D or 74 Megapixels in 2D with a horizontal visual acuity of 20/20 – almost 10 times the 3D resolution of the original CAVE.

A key feature of the CAVE2 design is the use of 3D capable LCD flat panel screens rather than rear projection, which enables more efficient use of facility space. In addition, the CAVE2 design also accommodates off-axis vertical viewing angles, eliminating any 3D ghosting at the top or bottom of the large viewing area.

The technology allows scientists to study phenomena too large, too small, too dangerous, too complex, or too distant to truly understand well without some help in perceptual augmentation. Once inside CAVE2, observers can adopt a scale, relative to the visual model, that makes them feel larger than a six-story building or smaller than a molecule, for example. This ability to zoom in and out of different scales empowers them to make detailed observations and gain new insights and knowledge.

CAVE2 is programmable using a number of application programming interfaces. While some are virtual-reality only, it is EVL’s SAGE (Scalable Adaptive Graphics Environment), that enables CAVE2’s huge wall to be partitioned into “windows”— enabling one or many 2D and 3D windows of information to simultaneously be displayed.

The development of the CAVE2 technology was funded by grants from the National Science Foundation and Department of Energy. Some of the royalties of licensing of the CAVE2 system will help fund future research at EVL.

Medical Imaging One of Many Uses

Fig. 1 – A simulation of human brain vasculature and cortical tissue is displayed in the CAVE2 Hybrid Reality Environment (Credit: Lance Long for EVL)

A team of neurosurgeons from the College of Medicine at UIC recently stepped into the CAVE2 to solve a vexing problem that presented itself in the arteries of the brain of a real patient.

“We were flabbergasted,” said Andreas Linninger, professor of bioengineering and lead researcher of a project that measures and models blood flow in the brains of patients with stroke.

For years, he and neurosurgeons had painstakingly used laptop and desktop computers to evaluate patient-specific images, which had been interpreted by computer algorithms to represent the brain and its blood flow in 3D. They pieced together arteries, veins, and micro-vessels to create 3D, full-brain models that physiologically mirrored the brains of individual patients, including a particular patient whose cerebrovascular system they were trying to accurately model. But because of the limited image spatial-resolution of even today’s best-quality PCs, there was something they just were not able to see. (See Figure 1)

“We had been looking at computer models of a particular patient’s brain for several months,” said Linninger, “but within five minutes of putting the model into the CAVE2, the chief endovascologist said we had connected certain arteries in a way that was inconsistent with anatomy.”

With that revelation, their model could be corrected. The method they used could someday benefit hundreds of thousands of Americans who fall victim to brain aneurysms and strokes, the third leading cause of death in the United States. (See Figure 2)

Where It Stands

Mechdyne Corporation, Marshalltown, IA, one of the world’s leading providers of innovative visual information technologies, licensed the CAVE2 hybrid reality environment in January 2013. Their licensing agreement continues the strong working relationship that began in 1994 when the company licensed the original CAVE technology.

Since CAVE 2 can be applied to numerous industries and research platforms, Mechdyne expects major users of the CAVE2 system will include universities, scientific research organizations, energy companies, and manufacturing and design organizations worldwide. The company also partners with a variety of higher education institutions to enable discovery and advance education through technology. Some of the institutions that have benefited from these virtual reality systems include: Arizona State University, Iowa State University, Washington University in St. Louis, MO, Bibliotheca Alexandrina in Egypt, and KISTI in the Republic of Korea.

For more information on CAVE2, visit http://info.hotims.com/45611-165 .