Designing 3D Interfaces

Examples of 3D interfacesPros and cons of 3D interfaces

Overview of 3D software and hardwareFour key design issues:

system performance, movement, presence, health & safety

What is a 3D interface?

Uses 3D graphics, possibly combined with specialised hardware, to give depth or perspective to the display of information

Utility:Extended GUIs

Realism:Immersive Interfaces

VisualisationVirtual

Environments

Degree of ‘utility versus realism’

Visualisation

Adding focus and context to 2D interfaces

3D visualisation of scientific data

Virtual Environments

Simulation Games

Pros and cons of 3D Pros:

create a sense of presence realistic simulation of physical space and objects more display space through focus + context

Cons: additional dimension to manipulate and control hard to map onto 2D displays and devices occlusion difficulty of remembering the locations of information requires greater hardware performance

3D interface software

Graphics libraries Objects (polygons and meshes), lighting, textures,

animation, collisions, physics (e.g., deformations), special effects (e.g., fog), cameras

With scripting User interaction, object behaviours, time-based actions

Sound Used for ‘spot effects’, soundtrack, and speech Spatialisation

Supporting tools Modelling and animation 2D art work - textures

Specialised 3D interface hardware

Hardware characteristics

Output Field of view Resolution Frame rate Stereo or mono Extent of exclusion of physical world (Locally) Shared or individual Degree of encumberance Force Feedback

More hardware characteristics

Input Degrees of freedom of movement sensing Range Accuracy Jitter Physical stability (for public use)

Key Design Issues

System performance Movement Presence Health and safety

System performance

Real-time performance is the often the most vital factor for 3D interfaces Maintain high frame-rate Rapid interaction with minimal latency Download size for online

Movement Up to six DOF required But, the input device may

support fewer make frequent movements direct less frequent require special

actions - additional mouse buttons, keys or special vehicles

but watch out for loss of parallelism - e.g., rotation as a single action

Also need to design manipulations – point, select, drag, rotate, resize, carry etc

Presence

A mental state where participant has the sense of being in the location specified by the displays - “being there”

A fundamental goal of VR? Measuring presence

subjective presence behavioural presence

Factors that affect presence

Immersion Mode of navigation Self-body image External disruptions Inconsistencies between the user’s mental

model of the world and its actual behavior Boredom and amount of activity

Health and Safety Possible effects

sickness postural instability psycho-motor coordination

Four factors the VR system the virtual environment the user the task

Health & Safety Guidelines

maintain frame rate > 20 hz, 8-15 hz may be especially bad

keep lag as low as possible don’t use HMD without other present inform users and encourage small head

movements avoid awkward postures for sustained

periods