Introduction to Virtual Environments Slater, Sherman and Bowman readings

Definition of Virtual Reality My working definition: –Interactive, multisensory, 3D computer- generated; involves some degree of immersion

Content of a Virtual Environment Objects with properties: description and state Actors, participants, avatars Real-time Geometric realism; illumination realism, behavioral realism

Visual realism influenced by: –field of view (FOV)—the size of the visual field that can be viewed instantaneously –field of regard (FOR)—the total size of the visual field surrounding the user –display size –display resolution –3D or degree of stereoscopy –head-based rendering—display of images based on position and orientation of head – realism of lighting –frame rate and refresh rate

Content of a VE – con’t Realism and real-time Representations Interaction Inputs and outputs Interface Navigation Behaviors Presence and immersion

Applications of VEs Entertainment Training and simulations; education Therapies and treatments Communication Benefits of immersion (not necessarily a full VE): spatial understanding, decrease in clutter (focus on task), increase in bandwidth

Fear of Heights project

Presence and Immersion Immersion: objective level of sensory data –Visual –Auditory –Haptic, olfactory, etc. Presence: sense of being there; user’s subjective psychological response

“Reality is virtual” Stereo cues- binocular disparity, accommodation (bringing into focus), convergence (near and far) Linear perspective Texture gradient Shadows and shading Occlusion Lighting Time and space constancy

Illusions Illusions from htm and and nizsas-triangle-and-marketing-101.html htm

Kanizsa’s triangle

/OpticalIllusionshttp://ccl.northwestern.edu/netlogo/models /OpticalIllusions

Ames Room

Virtual Environments A VR experience has: –Virtual world –Immersion; presence or mental immersion –Sensory Feedback –Interactivity Other terms: virtual reality, augmented reality, telepresence

Medium Many different kinds of mediums (which then have a virtual world): imagination (daydream), storytelling, painting (Mona Lisa), novels, maps, songs, films, puppetry (performance), , board games, video games, social media Medium->virtual world->composition-> experience Role of interaction

Authorship vs Creatorship Author: original producer Creator: could be many at different points eg: Gershwin wrote “Summertime” – he is the author- Janis Joplin did a version that is profoundly different- is she an author?

Terms Narrative: sequence of events –Plot, storyboard –Can be passive or interactive –Relationship to space and time –Directed or undirected –Examples in video games or music Interactivity –Control in the virtual world, behaviors –Affects whether narrative is directed or undirected –Examples in video games or music

Additional Terms (con’t) Form: how the narrative constructed and presented; interface; method of interaction –Flying, walking, navigation, wayfinding –Selection, manipulation of objects, interactions –Examples in video games or music Genre: categorization of style –Games, visualizations, virtual heritage, training –Examples in video games or music

User Interface to Virtual World Can be different from a computer Can be technological or not (performance) What is the interface to a music concert, dance performance, novel, TV, DVD We assume experience with interfaces; in computers what are some of these assumptions? In a virtual world what are the interface expectations?