Testing the usability of 3D immersive virtual environments presents several challenges that are not faced when evaluating 2D computer user interfaces. This paper describes the methodological lessons learned in the testing of the usability of the Wii input device in the 3D Virtual Collaboration Areana (VirCA, virca.hu) immersive virtual environment in an empirical formative study. A team of researchers at the Department of Ergonomics and Psychology at the Budapest University of Technology and Economics set out to test the Wiimote input device on basic navigation, object manipulation, and menu interaction tasks. The environment also included an abstract 3D emotion display object. This object was powered by an eto-motor modeling animal behavior developed by the ETOCOM team at the Computer and Automation Research Institute of the Hungarian Academy of Sciences in collaboration with the Department of Ethology, Etvs Lornd University. The study combined qualitative and quantitative methods to explore the usability of the interaction methods in the 3D environment. Three pilot and fourteen main study participants carried out two tasks in the 3D immersive environment after a brief training. Their behavior was observed and video-recorded. They were interviewed about their experience immediately after the interaction. The participants also filled out a demographic questionnaire, the Myers-Briggs Type Indicator (MBTI) personality type questionnaire, the Paper Folding Test (VZ-2) measuring spatial-visual ability through mental rotation tasks and the Reading the Mind in the Eyes Test (RMET). This paper summarizes the methods used in the study and recommendations for the evaluation for 3D immersive virtual environments.