The traditional computer interface provides a two-dimensional (2D) interface to design. The monitor is a two-dimensional visual display and the desktop mouse is a two-dimensional input device. These tools are sufficient for designing 2D products such as planar linkages. When these tools are used to design three-dimensional (3D) products however, the designer must learn how to use the 2D tools to interact with objects defined in three-dimensional space. Virtual reality technology provides truly three-dimensional tools, with position tracked visual displays and input devices, that allow interaction with 3D digital products. Over the last few years we have developed a virtual environment for spatial mechanism design [1–4]. This paper describes the differences between designing a spatial mechanism using traditional computer interfaces and designing using the VRSpatial application.