Controlling Navigation

Motivation

  • Different types of worlds require different styles of navigation
    • Walk through a dungeon
    • Fly through a cloud world
    • Examine shapes in a CAD application
  • You can select the navigation type
  • You can describe the size and speed of the viewer’s avatar

Selecting navigation types

There are five standard navigation keywords:

  • WALK - walk, pulled down by gravity
  • FLY - fly, unaffected by gravity
  • EXAMINE - examine an object at “arms length”
  • NONE - no navigation, movement controlled by world not viewer!
  • ANY - allows user to change navigation type

Some browsers support additional navigation types.

Specifying avatars

  • Avatar size (width, height, step height) and speed can be specified

Controlling the headlight

  • By default, a headlight is placed on the avatar’s head and aimed in the head direction
  • You can turn this headlight on and off
    • Most browsers provide a menu option to control the headlight
    • You can also control the headlight with the NavigationInfo node

Syntax: NavigationInfo

A NavigationInfo node selects the navigation type and avatar characteristics:

  • type - navigation style
  • avatarSize and speed - avatar characteristics
  • headlight - headlight on or off

XML Encoding

<NavigationInfo
  type='"WALK", "ANY"'
  avatarSize='0.25, 1.6, 0.75'
  speed='1.0'
  headlight='true'/>

Classic Encoding

NavigationInfo {
  type       [ "WALK", "ANY" ]
  avatarSize [ 0.25, 1.6, 0.75 ]
  speed      1.0
  headlight  TRUE
}

Summary

The navigation type specifies how a viewer can move in a world:

  • walk, fly, examine, or none

The avatar overall size and speed specify the viewer’s avatar characteristics.