Since 1938, the Ballistic Research Laboratory at Aberdeen Proving Ground, Md., was the center for the United States Army's research efforts in ballistics and vulnerability/lethality analysis. That remained the case until 1992, when BRL was disestablished and its mission, personnel and facilities were incorporated into the newly created U.S. Army Research Laboratory.
But during the decades of providing support to the nation, BRL quickly became involved in the move toward modern computing. Indeed, nearly 70 years ago, BRL unveiled the Electronic Numerical Integrator and Computer — ENIAC, the world's first operational, digital computer.
The development of this computer was driven by the Army's need to speed calculation of firing tables. And ever since the development of the ENIAC, ARL has provided the U.S. military with unprecedented scientific computational capabilities.
One such capability was BRL-CAD.
As its name suggests, BRL-CAD — a computer-aided design system — was developed before ARL existed. It has been used for nearly three decades in support of modeling, simulation and engineering analyses of military assets and their environments including the design and analysis of vehicles, mechanical parts and architecture.
Dr. Paul Tanenbaum, director of the Survivability/Lethality Analysis Directorate, used BRL-CAD early in his career when he was an analyst at the bench and then later when he served on the team developing and maintaining it.
"BRL-CAD is used in many types of analysis, and most particularly for ballistic vulnerability and lethality. Essentially every major vehicle and weapon system that the Army has acquired, or seriously considered acquiring, over the past quarter century has been analyzed by SLAD with BRL-CAD in conjunction with our other modeling tools," Tanenbaum said. "In order to simulate in software the accurate details of a weapon's effects on a target vehicle, you need a thorough and precise characterization of that vehicle's geometry, materials, componentry, et cetera. And you need to be able to very quickly process lots of queries of the form, 'what would a penetrator encounter if it proceeded along such-and-such a trajectory?' Those are BRL-CAD's two central capabilities: to represent system geometry and to query the daylights out of it."
Tanenbaum explained the importance of BRL-CAD to executing his directorate's mission.
"This ray-tracing, or shotlining, is central to SLAD's MUVES model (the analytical tool for vulnerability/lethality analyses of ballistic damage mechanisms against air and ground-mobile targets), which then walks threats along the trajectories, assesses how far they'd penetrate and what they'd hit, and concludes what would break, and thus which system capabilities would be lost and which retained," Tanenbaum said.
"So BRL-CAD is at the heart of SLAD's contributions to Army studies, live-fire test and evaluation, a host of major acquisition decisions, and even data tools that operational forces use in weaponeering, which is their pre-mission selecting of an optimum munition load to carry with them into an upcoming fight," he said.
C. Sean Morrison, from SLAD's Software Development Branch has worked on BRL-CAD for more than a decade. He began working at ARL as a summer student in 1998.
"The CAD industry is 'big' to say the least — about $6 billion last year, if I recall correctly," said Morrison. "Nearly everything around you — your computer, chair, desk, pen, phone, car and house — was modeled and built with the help of CAD software. The industry is about the same size as the computer gaming industry, but isn't as visible since it's not something you'd likely use at home. It's complicated software that usually requires lots of training."
BRL-CAD is extensively cross-platform supporting Windows, Mac OS X, Linux, BSD, Solaris and more. Morrison said that the huge game-changer was in 2004 with the conversion of BRL-CAD into a free open source software system. As open source, it expanded international visibility and participation in the project to unprecedented levels.
"We went from over 2,000 site licenses acquired over a 15-year period to more than 2,000 downloads in the first month alone," said Morrison. "We're now averaging more than 10,000 downloads per month and millions of website hits per year," he added.
Morrison said that just seven years after converting to open source, BRL-CAD surpassed a million downloads.
"The Open Source Initiative describes open source as a development method for software that harnesses the power of distributed peer review and transparency of process. It's more than just providing access to source code," said Morrison. "Open-source software must comply with specific criteria that ensure others have the freedom to redistribute the software and make modifications. It encourages collaboration."
BRL-CAD is recognized throughout the open-source industry.
According to an article written by Black Duck Software, the company that owns Ohloh, the oldest project on Ohloh is BRL-CAD. The history of this project dates back to 1979 when BRL needed CAD tools to help with simulations for combat vehicle systems. The article states that the BRL-CAD source code repository is believed to be the oldest public, version-controlled code base in the world that's still under active development, dating back to Dec. 16, 1983. With more than one million lines of primarily C code, and 48,500 commits, this project continues to be active 30 years later.
"They scanned half a million source code repositories that they track and found that BRL-CAD was the oldest, still being actively developed surpassing even other wildly popular open source projects," said Morrison. "There are hundreds of thousands of open-source projects out there — Linux, Firefox, Drupal, WordPress, Apache Web Server, Open Office, GIMP. I guarantee you've used some of them without even knowing it. You've indirectly used dozens of open source technologies just by sending an e-mail."
The BRL-CAD open-source community continues to engage in international collaboration. BRL-CAD was recently selected to participate in Google Code-in, a contest run by Google encouraging pre-university students ages 13-17 to get involved with open source. It is intended to help students who may have wanted to get involved but didn't know where to start. The program runs through Feb. 4, when the Google Open Source Programs Office announces the winners via their blog post.
"This is a great opportunity where we can mentor students that will work our 'itty-bitty' tasks related to code, documentation/training, outreach/research, quality assurance, and user interface," Morrison said. "It's impressive that BRL-CAD is still being actively and continuously developed and improved after 30 years. BRL-CAD is more active than ever due to the conversion to open source."