Introduction to Virtual Reality
~5 min read
XRVRvirtual-realitycomputer-graphicsstereoscopyimmersionmotion-trackingmetaverse
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Virtual reality (VR) sits at the intersection of computer graphics, human perception, and interaction design. It's not just strapping a screen to your face — it's the art of convincing the human brain that a computer-generated environment is real enough to inhabit.
There is no single definition. Three influential ones:
Ivan Sutherland (1965), the godfather of computer graphics: "In the ultimate display, one will not look at that world through a window, but will be immersed in it."
Steve Bryson (1996): "Virtual Reality refers to the use of three-dimensional displays and interaction devices to explore real-time computer-generated environments."
Thies Pfeiffer (2012): "Interactively generated 2nd order multimodal sensory perceptions, which are taken as 1st order perceptions by humans."
Despite the differences, three features are universal: immersion (the perception of being present in an environment), interaction with that environment, and real-time responsiveness.
VR builds on computer graphics. Every 3D object in VR is constructed from the same primitives: vertices (points in 3D space), edges (lines connecting vertices), and faces (triangles forming surfaces). The Utah Teapot — the "Hello World" of 3D graphics — demonstrates these concepts.
Different graphics APIs use different coordinate systems:
| System | Right/Left Hand | Up Axis | Forward |
|---|---|---|---|
| OpenGL | Right-handed | Y | -Z |
| Direct3D | Left-handed | Y | +Z |
| Unity | Left-handed | Y | +Z |
| Unreal | Left-handed | Z | +X |
Converting between systems is essential when integrating assets from different tools.
Understanding the human visual system is critical to building comfortable VR.
Key constraints:
When the visual system and vestibular system disagree, simulator sickness results. Symptoms include nausea, headache, dizziness, blurred vision, and fatigue — measured by the SSQ (Simulator Sickness Questionnaire, Kennedy et al. 1993).
Mitigation strategies: high frame rates (≥90 Hz), accurate stereoscopic rendering, dynamic field of view adjustment during motion, and minimizing latency between head movement and display update.
Jaron Lanier is often called the "father of VR" — he coined the term and founded VPL Research in 1984, producing the first commercial VR hardware (the DataGlove and EyePhone). Before Lanier, Myron Krueger used the term "artificial reality" for his interactive installations in the 1970s.
Key milestones:
Milgram and Kishino (1994) introduced the Reality-Virtuality (RV) Continuum, placing environments on a spectrum:
Real ──── Augmented ──── Augmented ──── Virtual
Environment Reality Virtuality Environment
Augmented Reality (AR) overlays digital content onto the real world (phone AR, HoloLens). Augmented Virtuality (AV) brings real-world elements into virtual environments. Virtual Reality (VR) is fully immersive and computer-generated.
Rauschnabel et al. (2022) extended this to "xR" — an umbrella term covering VR, AR, MR (Mixed Reality), and everything in between.
Modern VR devices fall into three categories:
| Category | Examples | Key Feature |
|---|---|---|
| PC-tethered | Valve Index, HTC Vive Pro 2, Pimax | Highest fidelity, external tracking |
| Standalone | Meta Quest 3, Pico 4, HTC Vive XR Elite | Inside-out tracking, no PC required |
| Console | PlayStation VR2 | Console ecosystem integration |
Tracking systems determine where the user's head and hands are in 3D space:
Immersion is the objective, technical capability of a VR system: display resolution, field of view, refresh rate, tracking precision, audio quality.
Telepresence (or "presence") is the subjective feeling of "being there." It's what happens when the technical immersion is good enough that your brain suspends disbelief.
High immersion doesn't guarantee presence, but low immersion makes it nearly impossible. The sweet spot: ≥90 Hz refresh, ≤20 ms motion-to-photon latency, ≥110° FOV, and accurate positional audio.
The metaverse extends VR beyond single experiences into a persistent, interconnected virtual universe. Key characteristics:
Major corporate players include Meta (Horizon Worlds), Epic Games (Fortnite ecosystem), and Apple (Vision Pro spatial computing platform).
For a complete deep dive with visuals and additional detail, download the university lecture slides: