Partis may be linear, radial, clustered, or fall into many other categories of geometric arrangement. In all cases, however, it is used to provide the participant with a broad understanding of how the architecture is organized. By developing a design with enough variety of forms and spaces, yet keeping them organized clearly, landmarks in the grid are established. They are critical to orientation in both the physical and the virtual realms. These orienting devices are accomplished in both the physical and the virtual realms by use of color and texture, lighting, and atmospheric and linear perspectives.
Solid colors require less computational overhead than textures in virtual environments as well.
The visibility of atmosphere, like mist, can establish some depth cueing in the physical world, but too much of it, like fog or smoke, can disorient participants. The same is true of the virtual realm, although heavier mist or fog can actually aid one s orientation in the virtual world by exaggerating depth cues and eliminating distant, distracting elements. However, without the context and constraints of horizons and gravity, there is no inherent sense of up and down. Participants navigate using cognitive maps, varying degrees of freedom, and by a combination of environmental cues and tools. For a participant to establish a cognitive map in an environment, whether physical or virtual, that person must be able to move and explore freely in the environment.