] > X3D Classic VRML encoding 4.0 draft - ISO/IEC 19776-2:202x - 7 Conformance

Extensible 3D (X3D) encodings
Part 2: Classic VRML encoding

7 Conformance

TODO, review: adjust to match corresponding organization as found in 19776-1 XML encoding Conformance, 9776-2 Classic VRML encoding, and 19776-3 Compressed binary encoding Conformance. Consistent document structure will further assist in creation of future X3D Encoding specifications (e.g. EXI, JSON, Turtle).

7.1 Introduction and topics

This clause addresses conformance of Classic VRML encoded X3D files, and conformance of X3D generators and X3D browsers that support the Classic VRML encoding.

7.1.1 Topics 7.1.2 Topics

Table 7.1 lists the topics in this clause.

Table 7.1 — Topics

7.1 Introduction and topics
    7.1.1 Introduction
    7.1.1 Topics 7.1.2 Topics
    7.1.2 Objectives 7.1.3 Overview
    7.1.3 Scope

7.2 Conformance
     7.2.1 Conformance of Classic VRML encoded files
     7.2.2 Conformance of Classic VRML encoding generators
     7.2.3 Conformance of Classic VRML encoding browsers

7.1.2 Objectives 7.1.3 Overview

Editors note, completed: the following section moved to 7.1.3

Conformance is defined for Classic VRML encoded files, for X3D generators that produce such files, and for X3D browsers that support Classic VRML encoded files. Conformance to an X3D profile is specified as related to technology in this part of ISO/IEC 19776.

This clause does not define the application requirements or dictate application functional content within an X3D file.

The primary objectives of the specifications in this clause are:

to promote interoperability by eliminating arbitrary subsets of, or extensions to, ISO/IEC 19775;
to promote uniformity in the development of conformance tests;
to promote consistent results across X3D browsers;
to facilitate automated test generation.

7.1.3 Scope

Conformance is defined for X3D models written as Classic VRML encoded files and for X3D browsers which support Classic VRML encoded files. For X3D generators, conformance guidelines improve the likelihood of successful interoperability. A concept of conformance to an X3D profile is introduced along with the rules which apply to this encoding.

This clause addresses the X3D data stream and implementation requirements. Implementation requirements include the latitude allowed for X3D generators and X3D browsers. This clause does not directly address the environmental, performance, or resource requirements of the generator or browser. This clause does not define the application requirements or dictate application functional content within a X3D file.

The scope of this clause is limited to rules for the open interchange of X3D content using the Classic VRML encoding.

7.2 Conformance

7.2.1 Conformance of Classic VRML encoded files

An X3D file is syntactically correct according to this part of ISO/IEC 19776 if the following conditions are met:

The X3D file contains as its first element an X3D header statement (see 4.3.2.2 Header statement syntax).
The X3D file contains as its second element an X3D PROFILE statement (see 4.3.2.3 PROFILE statement syntax).
Any COMPONENT statements (see 4.3.2.4 COMPONENT statement syntax) in the X3D file immediately follow the PROFILE statement.
Any UNIT statements (see 4.3.2.5 UNIT statement syntax) in the X3D file immediately follow any COMPONENT statements or the PROFILE statement if there are no COMPONENT statements.
Any META statements (see 4.3.2.6 META statement syntax) in the X3D file immediately follow any UNIT statements or any COMPONENT statements if there are no UNIT statements or the PROFILE statement if there are neither UNIT nor COMPONENT statements.
All entities contained therein match the functional specification of the corresponding entities of ISO/IEC 19775-1 X3D Architecture. The X3D file shall obey the relationships defined in the formal grammar and all other syntactic requirements.
The sequence of entities in the Classic VRML encoded file obeys the relationships specified in ISO/IEC 19775-1 producing the structure specified in ISO/IEC 19775-1.
All field values in the Classic VRML encoded file obey the relationships specified in ISO/IEC 19775-1 producing the structure specified in ISO/IEC 19775-1.
No nodes appear in the X3D file other than those allowed by ISO/IEC 19775-1 unless required for the Classic VRML encoding technique or those defined by the PROTO or EXTERNPROTO entities.
The X3D file is encoded according to the specification in this part of ISO/IEC 19776.
The X3D file does not contain behaviour specified as undefined in ISO/IEC 19775-1.

A Classic VRML encoded X3D file conforms to the profile specified in its header statement to a particular profile if:

It is syntactically correct.
It meets the restrictions of the profile as defined in the requirements annexes of ISO/IEC 19775-1 or in other parts of ISO/IEC 19775.

A Classic VRML encoded X3D file conforms to individual components if:

The X3D file conforms to the specified profile.
The X3D file meets the restrictions of the component and component support level as defined in ISO/IEC 19775-1 X3D Architecture for that component.
It contains only the nodes and statements allowed by the specified PROFILE and COMPONENT statements.

7.2.2 Conformance of Classic VRML encoding generators

A Classic VRML encoding generator conforms to this part of ISO/IEC 19776 if all X3D files that are generated are syntactically correct according to the provisions of this part of ISO/IEC 19776.

A Classic VRML encoding generator conforms to a particular profile if it can be configured such that all X3D files generated while in that configuration conform to that particular profile.

A Classic VRML encoding generator conforms to a particular component if it can be configured such that all X3D files generated while in that configuration conform the specified component and component support level.

7.2.3 Conformance of Classic VRML encoding browsers

An X3D browser that supports the Classic VRML encoding conforms to a particular profile if:

It is able to read any Classic VRML encoded file that conforms to that particular profile.
It presents the graphical and audio characteristics of the X3D nodes in any Classic VRML encoded file that conforms to the that particular profile, within the latitude defined in the specification for that particular profile.
It correctly handles user interaction and generation of events as specified in ISO/IEC 19775-1 X3D Architecture, within the latitude defined in the specification for that particular profile as defined in the annexes of ISO/IEC 19775-1 or in other parts of ISO/IEC 19775.
It satisfies the requirements of that particular profile in regard to minimum support requirements as defined in the specification for that particular profile.
It satisfies the general conformance requirements for browsers as stated in the Conformance clause of 6 Conformance of ISO/IEC 19775-1.

An X3D browser that supports any Classic VRML encoded file that contains COMPONENT statements conforms to the specified component if:

It is able to read all nodes and/or statements required by that component when encoded in the Classic VRML encoding.
It does not allow any nodes and/or statements that are specified for a component support level that exceeds the level specified in the COMPONENT statement.