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description
Interaction Techniques for Interaction Techniques for Common Tasks in Immersive Common Tasks in Immersive
Virtual EnvironmentsVirtual EnvironmentsDesign, Evaluation, and ApplicationDesign, Evaluation, and Application
Doug A. Bowman
April 27, 1998
Doug Bowman - VE Interaction Techniques 2
VisionVision
Immersive VEs for productivity
Complex applications for real work
Example: immersive modeling and design
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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DefinitionsDefinitions
Interaction Technique (IT): Method used to complete a task via a human-computer interface (hardware & software)
Immersive VE: A real-time 3D synthetic environment that appears to surround the user in space√ HMD with head tracking, CAVEX“Fishtank VR”, MUDs, Multimedia apps
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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A Brief History of VEsA Brief History of VEs
1968: Sutherland’s Ultimate Display Hardware advances
– displays – trackers – 3D graphics– input devices – haptics – 3D audio
Software advances– view culling – level of detail– VE toolkits – collision detection
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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VE ApplicationsVE Applications
In Use:– architectural walkthrough– phobia treatment– games (e.g. 1st person shooter)
Proposed:– information visualization and retrieval– modeling and design– constructivist education
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Interaction: the Interaction: the Distinguishing FactorDistinguishing Factor
Current applications– may involve movement through VE– may involve shooting or pointing
Proposed applications– require 3D navigation and selection– require 6 DOF manipulation (object placement)– require large command spaces
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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How to improve VE How to improve VE InteractionInteraction
better design of techniques systematic evaluation (formative and
summative) in the context of applications and
requirements
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Universal Tasks: TravelUniversal Tasks: Travel
Viewpoint Motion Control: The user’s interactive control of the position and orientation of his viewpoint
Wayfinding: Cognitive process of determining a route, using landmarks, maps, etc.
Navigation: VMC + Wayfinding
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Universal Tasks: Universal Tasks: Selection & ManipulationSelection & Manipulation
Selection: Specification of one or more objects from a set– as the object of a command– to begin manipulation
Manipulation: Specification of the position, orientation, and/or scale of an object
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Why not natural Why not natural interaction?interaction?
Term “VR” implies replication of real world
Why not use well-developed human skills to accomplish tasks in VEs?– travel: walking or driving– selection & manipulation: grasp and place
These mappings are intuitive, but too limited
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Interaction Techniques Interaction Techniques and Input Devicesand Input Devices
input devices are only the hardware component of an IT
input device does not determine IT many ITs can be implemented with a single
input device we will not design or evaluate devices we will design and evaluate ITs for common
VE input devices
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Problem Statement: Problem Statement: I I will...will...
analyze universal tasks and create taxonomies of techniques
design new techniques based on these formal frameworks
design, implement, and conduct formal evaluations of IT performance
apply the results to a complex and useful VE application
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Design and Evaluation Design and Evaluation MethodologyMethodology
Taxonomization and Categorization Guided Design Performance Measures Range of Evaluation Methods Testbed Evaluation
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Taxonomization and Taxonomization and CategorizationCategorization
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Task
Subtask
Technique Component
Task analysis Consider techniques for
low-level subtasks Promotes deeper
understanding of task Framework for design Framework for evaluation
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Guided DesignGuided Design
Design new techniques based on taxonomy, not simply intuition
Choose a component for each low-level subtask
Easy to see holes in design space
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Task
Subtask
Technique Component
1 2
3 4
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Evaluation MethodsEvaluation Methods
Range of performance metrics (quantitative and qualitative; productivity and user-centric)
Range of methods (user studies, usability evaluation, formal experiments)
Consideration of outside factors (characteristics of task, environment, user, system that might affect performance)
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Testbed EvaluationTestbed Evaluation
testbed: representative set of tasks and environments
evaluate techniques for overall performance in a wide range of situations
vary technique components and outside factors
measure several performance variables generalizable and replicable
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Summary of MethodologySummary of MethodologyIntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Taxonomies Perf. Metrics Outside Factorsspeedaccuracycomfort...
environment densityuser’s reachtask difficulty...
Initial Evaluation and Design
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IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Taxonomies Perf. Metrics Outside Factors
Applications
speedaccuracycomfort...
environment densityuser’s reachtask difficulty...
requirements
Initial Evaluation and Design
Summary of MethodologySummary of Methodology
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IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Taxonomies Perf. Metrics Outside Factors
TESTBED EVALUATION
Applications
speedaccuracycomfort...
environment densityuser’s reachtask difficulty...
requirements
Initial Evaluation and Design
Summary of MethodologySummary of Methodology
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IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Taxonomies Perf. Metrics Outside Factors
TESTBED EVALUATION
PerformanceMeasurements/
ModelsApplications
speedaccuracycomfort...
environment densityuser’s reachtask difficulty...
requirements
choice oftechniques
Initial Evaluation and Design
Summary of MethodologySummary of Methodology
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Informal EvaluationInformal Evaluation
based on observations– default gaze-directed steering– lack of published work
based on our own applications– Conceptual Design Space– Virtual GIS
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Initial TaxonomyInitial Taxonomy
Task: Move from the current location to the desired location
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Viewpoint MotionControl
Direction/TargetSelection
Velocity/AccelerationSelection
Conditions of Input
gaze-directedpointingphysical props
gestureslow in, slow outphysical props
start/stop buttonsautomatic start/stopconstant movement
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Performance MeasuresPerformance Measures
Quantitative (e.g. speed, accuracy) Qualitative (e.g. presence) User-Centric (e.g. ease of use, comfort)
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
IT Apps
Quality Factors-speed-accuracy-cognitive load-presence-spatial awareness- ...
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Simple ExperimentsSimple Experiments(Bowman, Koller, and Hodges, VRAIS ‘97)(Bowman, Koller, and Hodges, VRAIS ‘97)
Absolute Motion– no difference between gaze and
pointing Relative Motion
– pointing superior to gaze Spatial Awareness
– teleportation causes disorientation– any continuous motion does not
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Expanded FrameworkExpanded Framework
Absolute vs. Relative Motion– same techniques, different
results– highlights need to consider
outside factors Consider task, user, system,
and environment characteristics
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Task
Pe
rfo
rma
nce
absolute relative
gaze-directed steering
pointing
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Complex ExperimentComplex Experiment Does travel IT affect cognitive load? Task: gather as much info as
possible Variables:
» IT: gaze, pointing, torso» Environment: 1-, 2-, or 3-
dimensional» System: collision detection
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Guided DesignGuided Design
Taxonomy: “tour” technique– environmental target selection– gesture-based velocity selection– explicit or automatic stop inputs
Intuition: travel based on manipulation– cross-task technique– still fits in taxonomy
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Final Framework and Final Framework and TestbedTestbed
Rework taxonomy to be more general– task analysis: 2 basic position-setting methods
are specifying destination, specifying trajectory– distinction allows better fitting of techniques
VMC Testbed– still in design stage– based on evaluation framework
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Initial TaxonomyInitial Taxonomy
Based on metaphor, not task Arm-extension metaphor
– touch and place object with virtual hand– hand may extend beyond normal range
Ray-casting metaphor– point at object to select– manipulate by attaching to virtual light ray
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Informal EvaluationInformal Evaluation(Bowman and Hodges, I3DG ‘97)(Bowman and Hodges, I3DG ‘97)
Studied six techniques (4 AE, 2 RC) Simple user study (comments, observations) Eleven subjects used techniques to place
furniture in a room Results
– AE excels at manip., RC better at selection– selection & manipulation should be separated
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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HOMER TechniquesHOMER Techniques
Hand-Centered Object Manipulation Extending Ray-Casting
Hybrid technique Select: ray-casting Manipulate: v. hand
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Time
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HOMER TechniquesHOMER Techniques
Hand-Centered Object Manipulation Extending Ray-Casting
Hybrid technique Select: ray-casting Manipulate: v. hand
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Time
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HOMER TechniquesHOMER Techniques
Hand-Centered Object Manipulation Extending Ray-Casting
Hybrid technique Select: ray-casting Manipulate: v. hand
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Time
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HOMER TechniquesHOMER Techniques
Hand-Centered Object Manipulation Extending Ray-Casting
Hybrid technique Select: ray-casting Manipulate: v. hand
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Time
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Formal TaxonomyFormal Taxonomy
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Selection
Manipulation
Release
Indication of Object
Indication to Select
Attachment
Positioning
Orientation
Indication to Release
Final ObjectPosition/Orientation
touchocclude
buttongesture
hand moves to objectuser scales to touch object1-to-1hand motion mapping
match tracker orientationindirect control
buttongesture
remain in placeuse physics model
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Evaluation FrameworkEvaluation Framework
Performance measures similar to travel Important outside factors:
– task characteristics: DOFs to manipulate– user characteristics: reach, spatial ability– system characteristics: constraints used
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Guided DesignGuided Design
testbed implemented to allow arbitrary combinations of technique components
4608 possible combinations - reduced to 667 via dependencies and constraints
Taxonomy: gaze-based HOMER with separate positioning and orientation
Intuition: manipulation based on travel (cross-task technique)
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Selection/Manipulation Selection/Manipulation TestbedTestbed
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
Tasks that test all important aspects of a select/manip. IT
Selection variables: distance, size, density
Manip. variables: distance, accuracy, DOFs required
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Application Case Study: Application Case Study: Immersive DesignImmersive Design
Verify evaluation results in a complex VE application
Design system involves all universal tasks
Choose ITs based on testbed results and specified application requirements
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Interaction RequirementsInteraction Requirements
Travel– exploration and goal-based movements– spatial awareness, info gathering, ease of use
Selection– accuracy at a distance, speed, comfort
Manipulation– expressibility, accuracy, ease of use
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Three Levels of Three Levels of Interaction DesignInteraction Design
Naive design– taken from CDS application(in D. Bertol, Designing Digital Space)
– gaze-directed steering, ray-casting “Intuitive” design iteration
– current implementation– pen & tablet, pointing, Go-Go technique
Final, systematic design
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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Remaining WorkRemaining Work
complete design and evaluation framework for travel
design, implement, and run travel testbed complete and run selection/manipulation
testbed modify application interaction design and
verify with a usability study
IntroductionMethodologyTravelSelection/ManipulationApplicationRemaining Work
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ContributionsContributions
formal understanding of tasks/techniques testbeds for future evaluations performance results and models new interaction techniques useful and usable immersive design
application