An abstract view

**Figure 2.2:** Under normal conditions, the brain (and body parts) control the configuration of sense organs (eyes, ears, fingertips) as they receive natural stimulation from the surrounding, physical world.
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**Figure 2.3:** In comparison to Figure 2.2, a VR system ``hijacks'' each sense by replacing the natural stimulation with artificial stimulation that is provided by hardware called a display. Using a computer, a virtual world generator maintains a coherent, virtual world. Appropriate ``views'' of this virtual world are rendered to the display.
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**Figure 2.4:** If done well, the brain is ``fooled'' into believing that the virtual world is in fact the surrounding physical world and natural stimulation is resulting from it.
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Figure 2.2 illustrates the normal operation of one of our sense organs without interference from VR hardware. The brain controls its configuration, while the sense organ converts natural stimulation from the environment into neural impulses that are sent to the brain. Figure 2.3 shows how it appears in a VR system. The VR hardware contains several components that will be discussed shortly. A Virtual World Generator (VWG) runs on a computer and produces ``another world'', which could be many possibilities, such as a pure simulation of a synthetic world, a recording of the real world, or a live connection to another part of the real world. The human perceives the virtual world through each targeted sense organ using a display, which emits energy that is specifically designed to mimic the type of stimulus that would appear without VR. The process of converting information from the VWG into output for the display is called rendering. In the case of human eyes, the display might be a smartphone screen or the screen of a video projector. In the case of ears, the display is referred to as a speaker. (A display need not be visual, even though this is the common usage in everyday life.) If the VR system is effective, then the brain is hopefully ``fooled'' in the sense shown in Figure 2.4. The user should believe that the stimulation of the senses is natural and comes from a plausible world, being consistent with at least some past experiences.