DOM Environment Organization

An X3D scene is conceptually defined as a seqence of statements organized into a block of statements. The block may be embedded in an HTML file or in it's own file where the block comprises the entirity of the file. The first item of the block is the X3D declarative tag that identifies the block of statement along with various parameters. The parameters include profile and extension to determine the specific capabilities required by the X3D scene. After the X3D declarative tag a UNIT and/or META (in that order) may appear. The remainder of the block consists of the other elements defined here.

ROUTE statements are used to specific the pathways for allowed transmissions of events. These statements link a field in one node to a field of the same type in another node.

Any additional X3D content loaded into the scene via Inline nodes or scenes loaded using createX3DFromStream, createX3DFromString, or createX3DFromUrl, shall be declared as having a profile and extension that has an equal or smaller set of required functionality; i.e., there can be no extensions explicitly declared, or implied by the profile in that content, that requires functionality not declared in the original profile and extension declarations for the containing scene.

X3D Declarative Tag

The Header statement is an encoding-dependent statement containing the following elements:

1. version of the standard being supported (for this version of this part of ISO/IEC 19775, the version number is "4.0");
2. identification of the character encoding being supported (for this standard, this shall be "UTF-8"), and
3. optional comments that may apply to the file.

While the exact representation of this information is dependent on the encoding, this information shall always be stored as human-readable text.

The default value for an X3D Declarative tag in an HTML is as follows:

• Profile: HTML
• Extensions: none
• Version: V4.0
• Character Encoding: utf-8

These parameters can be omitted if the needed values are the same as the default.

PROFILE Parameter

X3D scenes in an HTML file (implied DOM environment) are not require to include a profile designator. If the X3D scene (or scene-part) is contained in a separate file, then a PROFILE declaration must be included as specified in 7.2.5.3 PROFILE statement.

Extension Parameter

The Extension Parameter allows extensions to the specified profile to include features associated with that extension. Extensions include support for geospatial, cad, h-anim, and other modeling or control nodes. It is not required that a browser support an extension. If support is not available, those nodes shall be quietly ignored, though a message may be written to the console.

UNIT Statement

There is no change. See 7.2.5.5 UNIT statement for details.

META statement

There is no change. See 7.2.5.6 META statement for details.

ROUTE statement

There is no change. See 7.2.5.7 ROUTE statement for details.