Márcio Ricardo Martins

Abstract
The use of keyboard and mouse combinations to navigate 3D environments of virtual worlds requires the coordination of both hands in order for the 2D degrees of motion of the mouse to transform into the variety of motions available in a 3D space. Such coordination may pose a challenge to people with motor disabilities. 3D controllers known as "3D mice" are presented by manufacturers as significant interface alternatives. To establish the feasibility of such claims, the authors conducted a usability test of two 3D mice marketed by 3Dconnexion, in parallel with a keyboard + mouse test. The 10 participants had motor disabilities due to medullary lesions on vertebrae C5-D11 and performed 13 different tasks in the Second Life virtual world: 5 participants used 3D mice and 5 used keyboard + mouse. The main conclusion is that 2-3 of the 5 most challenging tasks in the keyboard + mouse combination become less challenging using 3D mice. Participants' feedback was more positive regarding 3D mice, but with significant differences between mice. Contrary to initial expectations of the authors, the least stable mouse, Space Navigator, produced the best feedback.