Adding Navigation Information

on this page: creating | know your avatar | apply and revert | headlight | viewer type | viewer speed | visibility limit | advanced

The Navigation Info Editor allows you to describe certain physical characteristics of the viewer and the viewing model. You can specify the default viewer to be used with your scene (Walk, Examiner, Fly, or none). You can also specify certain attributes for an avatar, which is a physical manifestation of the user at the current viewpoint in your world. You can specify the size of the avatar, which affects when collisions occur, as well as the height of the tallest objects over which the avatar can step.

Find it: Click the Navigation Info Editor button on the Editors palette:

Creating a NavigationInfo Node

Use the Create Global and Create Local buttons to create NavigationInfo nodes. As with lights and sounds, NavigationInfo nodes can be either global (they are placed at the root of the scene hierarchy and are not associated with any object) or local (they are placed under a Transform node along with their associated object or group of objects). (See also Global vs. Local.)

NavigationInfo nodes are a type of bindable node. The browser binds to the first NavigationInfo node it finds in the file. All subsequent NavigationInfo nodes are ignored unless the file also contains a Script node that binds the browser to other NavigationInfo nodes under certain conditions.

Getting to Know Your Avatar

An avatar is a physical manifestation of the user in the scene at the current viewpoint. The Size field specifies the allowable distance between the user's position in the scene and an object in the scene before a collision is detected. For example, if you specify a size of 2 and collision detection is enabled, any time the viewpoint comes closer than 2 meters to an object, a collision occurs. The default size is .25 meters.

The Height field indicates the distance above the terrain at which the browser should maintain the viewpoint. For example, if you want users to feel about 1.9 meters tall, specify a height of 1.9 so that their viewpoint (their avatar's head) is 1.9 meters above ground level. This field is used only for viewer types that use terrain following, such as the Walk viewer. The default height is 1.6 meters.

The Step field indicates the height of the tallest object over which the viewpoint can step without colliding into it. (You don't want users colliding with every pebble in their path; you simply want the browser to step over the pebbles.) This field is useful for building staircases with dimensions that can be ascended by all browsers. The default step is .75 meters.

Apply and Revert Buttons

When you click the Apply button, the values you've entered are saved as part of a NavigationInfo node in the file. When you click Revert, the field values return to the previous set of applied values. (Revert is not exactly like Undo because it goes back to the previously applied set of values, not simply the previous value.)

Headlight

Use the Headlight check box to specify whether the headlight should be on or off when the scene is loaded into the browser.

Viewer Type

The Viewer Type field allows you to specify which type of viewer the browser should use when the scene is initially loaded.

Viewer Type Defines this viewer in Cosmo Player* Viewer used for Viewer can be changed in browser
Any Walk (default) Letting people choose a viewer from within their browsers Yes
Walk Walk Navigating a world by walking through it No
Examine Examiner Looking at a world as if examining a single object No
Fly Fly Navigating a world by floating or flying through it No
None No viewer available Disabling viewer controls No
Any/Walk Walk Navigating a world primarily by walking through it Yes
Any/Examine Examiner Looking at a world primarily as if examining a single object Yes
Any/Fly Fly Navigating a world primarily by floating or flying through it Yes
Any/None No viewer available at first Letting people navigate with keyboard shortcuts Yes
*Other browsers may refer to the viewers by different names.

Viewer Speed

The Viewer Speed field refers to the rate at which the viewer travels through the scene. The default value is 1 meter per second. This value affects panning and dollying in the Examiner Viewer but does not affect rotation speed.

Visibility Limit

The Visibility Limit field sets the farthest distance the user is able to see. A value of 0 (the default) indicates infinite visibility. Values for this field must be greater than or equal to 0.

Advanced

See The VRML 2.0 Handbook, by Jed Hartman and Josie Wernecke, for a description of how to use a Script node to bind nodes such as the NavigationInfo node to the browser. Chapter 7, "Scripting," describes how the browser maintains a separate stack for each type of bindable node.

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