Lecture 5: Interaction and Navigation

Dr. Xiangyu WANG

Acknowledge the notes from

Dr. Doug Bowman

Universal interaction tasks

– Navigation• Travel – motor component• Wayfinding – cognitive component

– Selection– Manipulation– System control

• Selection & Manipulation– Selection: specifying one or more objects from

a set– Manipulation: modifying object properties

(position, orientation, scale, shape, color, texture, behavior, etc.)

• Selection performance– Variables affecting user performance

• Object distance from user• Object size• Density of objects in area• Occluders

• Manipulation enhancements– Constraints– 2-handed manipulation– Haptic feedback– Multi-modal manipulation

• Travel– the motor component of navigation– movement between 2 locations, setting the

position (and orientation) of the user’s viewpoint

– the most basic and common VE interaction technique, used in almost any large-scale VE

• You can travel techniques which do not address wayfinding, but the best travel techniques will integrate aids to wayfinding.

• Travel tasks– Exploration: thoughtless travel techniques– Search

• Naïve• Primed

– Maneuvering: short and precise movement, usually explicit travel techniques.

“Natural” travel metaphors

• “Natural” travel metaphors: useful for training– Walking techniques– Treadmills– Bicycles– Other physical motion

• VMC / Magic carpet• Disney’s river raft ride• Simulation of flying

Walking techniques

Bicycles as Travel Technique

Tang et al. 2007 (Virtual Bicycling Simulator project)

Bicycles as Travel Technique

Images from Virtual Environments Laboratory

Treadmill as Travel Technique

Mohler et al. 2004

Magic Carpet as Travel Technique

Magic carpet project

• Steering metaphor

• Target-based metaphor

• Route-planning metaphor

Travel Techniques

Travel Techniques

• Steering metaphor: continuous specification of direction of motion– gaze-directed– pointing– physical device (steering wheel, flight stick)

Travel Techniques

• Target-based metaphor– discrete specification of goal– point at object– choose from list– enter coordinates

• Map-based travel technique (a type of Target-based metaphor)– User represented by icon on

2D map– Drag icon with stylus to new

location on map– When released, viewpoint

animated smoothly to new location

Travel Techniques

• Route-planning metaphor– one-time specification of path– place markers in world– move icon on map

Travel Techniques

Travel Techniques

• Steering metaphor

• Target-based metaphor

• Route-planning metaphor

Steering metaphor Target-based metaphorRoute-planning metaphor

the relative amount of control by the user increases

the relative amount of control by the system increases

• Manipulation metaphor– manual manipulation of viewpoint– “camera in hand”

Travel Techniques

• Design guidelines– Make simple travel tasks simple (target-based

techniques for motion to an object, steering techniques for search).

• Provide multiple travel techniques to support different travel tasks in the same application.

Travel Techniques

• Implementation issues for travel techniques– Velocity / acceleration control: Gestures,

sliders, and speech control– World rotation– Constrained motion

• Constant height• Terrain-following

Travel Techniques