introduction to virtual environments slater, sherman and bowman readings

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 http://www.colorcube.com/illusions/illusion.htm and http://www.eyetricks.com/illusions.htm and http://illusionsetc.blogspot.com/2005/06/kanizsas-triangle-and-marketing-101.html

Kanizsa’s triangle

• http://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), email, 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?