|This article does not cite any sources. (January 2008)|
The Assassin 3D (A3D) by First-Person Gaming is a trackball designed to be used simultaneously with a joystick to replace the keyboard and mouse combo for player movement and aiming in first-person shooter games like Quake and Unreal. James Barnes, president of First-Person Gaming, designed the original Assassin 3D, released in Dec. 9, 1996. The controller original MSRP was $49.95, and was also sold in a $99.95 package including a Wingman Warrior Extreme, a very successful joystick developed for First-Person Gaming by Logitech.
The Assassin 3D patented technology  revolved around having a pass through gameport connection that received and filtered the analog signal from the joystick, combined it with the trackball data, and sent it in a single pass to the computer. The trackball was intended to be manipulated by the left hand, to orient the player view, while the right hand operated the joystick to move forward and backward and strafe left and right. Key advantages of the system:
1. High quality and ergonomic trackball device. Not only the system provides a comfortable and strain-free control system with no wrist torsion as in both keyboard and mouse operations, the quality of the components like the large and heavy ball and stainless steel bearings allowed for extremely smooth operation. Alas, like most opto-mechanic trackballs, the Assassin 3D required regular cleaning and maintenance, especially replacement bearings since they tended to wear out after three or four months of continuous use.
2. 100% accurate 180 degrees turn, not consistently possible even with modern mice. Basically the player positions one of his control fingers (generally index or ring) at the seam between the trackball and retention ring, either right or left edge, and perform a full revolution on the ball until hitting the retention ring on the other side. That makes checking your six, a very common and needed movement in first-person shooter games, a trivial and accurate task with little to no training.
3. Variable speed control. Mouse users generally rely on the W, A, S and D keys to navigate their in-game character in the virtual battlefield, in a digital fashion. Due to the binary nature of keyboards (the key is either depressed or not), there's no possible way to move slower than the maximum move speed. With the analog type of the recommended joysticks for the A3D, the player can apply less or more force to the joystick lever and get a similar percentage of his full-speed in game, basically allowing him the fine control needed to strafe-aim.
The combination of the trackball accuracy and joystick analog control allowed for sophisticated two-hand aiming, arguably unsurpassed to these days. Nevertheless, at near $100 for a quality combo it had too high a price tag for a just-born game genre, hence only few enthusiast gamers could afford and enjoy its benefits. After less than satisfactory sales, the Assassin 3D technology was sold to MadCatz. MadCatz released the same controller renamed as Panther, and later replaced it with the Panther XL model. As technology evolved, the very cpu-intensive gameport connection had its slow reading rate (30 polls per second) far surpassed by the PS/2 and USB connections, meaning A3D players couldn't compete with traditional mouse + keyboard players in response speed anymore. The gameport computer interface is rarely found in modern boards and isn't even supported by the Microsoft Vista operating system, meaning the original A3D is now a legacy device. The supposedly replacement unit, the Panther XL, didn't sport the same quality in components, with a light-weighted ball and a low quality built-in joystick.
After more than a decade being just a fond memory among its users, the original ergonomics and design of the original Assassin 3D was re-released by an Asian company, iOne Technology, named as the "Libra 90"., with modern PS/2 and USB connection capability.