Virtual Reality Modeling Language VRML

first, the basic concept

VRML is the acronym for "Virtual Reality Modeling Language" (Virtualrealitymodelinglanguage).

Node: The basic elements that make up the virtual world;

Routing: A way to transfer information between nodes.

VRML defines a series of objects used to realize three-dimensional scene, multimedia and interactivity. These objects are called nodes, and the nodes contain basic elements that are domain (field) and event, which are parameters that are contained in the node, and events are used for the delivery of parameters.

The domain and event domain (field) and event are the basic properties that VRML nodes use to define the nature of the object. Domains and events are defined by name, function type, numeric type, and default value. There is no sequential difference in the definition of domains and events in nodes. From the data structure, they can be divided into two categories, one of which contains only one value (a value can be a number.) a vector, or even an image, another point, and another class can contain multiple values, which can be thought of as arrays. The numeric type of a single-valued field or event is named starting with SF, a multivalued field, or an event that begins with MF.

Second, the editor

Writing VRML program using Text editor (Notepad, WordPad)
Using Vrmlpad (a tool specifically designed to write VRML programs) 3. The extension of the VRML 2.0 file must be WRL or Wrz for example: CAR.WRL (normal format)
BUS.WRZ (compressed format, available WinZip etc Open) 4. The first line of the VRML 2.0 file must be: #VRML V2.0 UTF8

Three, the common node introduction

1. Transform node

Function: Establish a local coordinate system, coordinate transformation of the body, so that the shape of the movement, rotation, proportional change

Common fields:

Rotation provides a rotational angle (four digits, first three numbers and the origin to construct the rotation axis, the fourth number gives the rotation angle, the right hand counterclockwise is the positive direction)

scale provides a factor for proportional amplification

Translation provides a value for panning

Children provides an object for coordinate transformations, which can be a body or another local coordinate system 2. Group node function: Transform node without coordinate transformation function, so it can be replaced by transform

3. Def and use action: a good way to name a node statement for reuse, Def, and using to shorten the program
4. Anchor node Action: Enables multiple VRML to generate links

Frequently used domains: URLs provide the file name of the link

Des Cription provides a description of the linked file

Parameter the way to provide links (open new window or overwrite old)

Children generates a link to the carrier (the mouse should click on the object) 5. Viewpoint node action: Determining the position of observation

Common fields: Orientation provides an angle of view

Position provides observation position 6. Background node Action: Set the display background, you can also set the picture on the background, up to six pictures can be pasted