Extensible 3D (X3D)
Part 1: Architecture and base components
This clause addresses conformance of X3D files, X3D generators and
The topics covered in this clause are shown in Table 6.1.
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.
Conformance is defined for X3D files and for X3D browsers. For X3D
generators, conformance guidelines are presented for enhancing the likelihood
of successful interoperability.
A concept of base profile conformance is defined to ensure interoperability
of X3D generators and X3D browsers. Base profile conformance is based
on a set of limits and minimal requirements. Base profile conformance is
intended to provide a functional level of reasonable utility for X3D generators
while limiting the complexity and resource requirements of X3D browsers.
Base profile conformance may not be adequate for all uses of X3D.
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.
6.2.1 Conformance of X3D files
An X3D file is syntactically correct according
to this part of ISO/IEC 19775 if the following conditions are met:
- The X3D file contains as its first element an X3D header
statement (see 188.8.131.52 Header
statement) specifying the version to which this file conforms. Versions and
associated content are specified in Annex L Version content.
- All entities contained therein match the functional
specification of entities of this part of ISO/IEC 19775 that correspond to
the version specified in the header statement. The X3D file shall obey the
relationships defined in the formal grammar and all other syntactic
- The sequence of entities in the X3D file obeys the
relationships specified in this part of ISO/IEC 19775 for the version
specified in the header statement producing the structure specified in the
part of ISO/IEC 19775 for the version specified in the header statement.
- All field values in the X3D file obey the relationships
specified in this part of ISO/IEC 19775 for the version specified in the
header statement producing the structure specified in this part of ISO/IEC
19775 for the version specified in the header statement.
- No nodes appear in the X3D file other than those specified for
the applicable profile as specified in this part of ISO/IEC 19775 unless
specified in a COMPONENT statement, are required for the encoding technique,
or are those defined by the PROTO or EXTERNPROTO entities should such be
available in the profile.
- No nodes or fields appear in the X3D file other than those
defined as part of the version specified in the header statement.
- The X3D file is encoded according to the rules of
- It does not contain behaviour described as undefined in this part of ISO/IEC
6.2.2 Conformance of X3D generators
A X3D generator is conforming to ISO/IEC 19775 if all X3D
files that are generated are syntactically correct and meet the requirements
state in 6.2.1 Conformance of X3D files.
A X3D generator conforms to a profile if it can be configured
such that all X3D files generated conform to that profile.
6.2.3 Conformance of X3D browsers
An X3D browser is conforming if:
- It is able to read any X3D file that conforms to the profiles
and components supported by that browser for the version(s)
and encoding(s) supported by that
- It implements the functionality specified for all abstract
interfaces, insofar as they are made available in concrete nodes derived
from those interfaces, within the latitude defined for the specified
profile, components, and version and as allowed in this clause.
- It presents the graphical and audio characteristics of the X3D
nodes in any X3D file that conforms to the applicable profile, components,
and version, within the latitude defined for the specified profile,
components, and version and as allowed in this clause.
- It correctly handles user interaction and generation of events
as specified for the applicable profile, components, and version, within the
latitude defined for the specified profile, components, and version and as
allowed in this clause.
- It satisfies the minimum support requirements for browsers for the
applicable profile as enumerated in the table of minimum support requirements
for that profile.
6.3 Minimum support requirements
6.3.1 Minimum support requirements for generators
There is no minimum complexity which is required of (or appropriate for) X3D
generators. Any compliant set of nodes of arbitrary complexity may be generated,
as appropriate to represent application content, and which produce only the
nodes allowed by the applicable profile, components, and version.
6.3.2 Minimum support requirements for browsers
Each profile defines the minimum complexity which shall be supported
by an X3D browser in support of that profile. Browser implementations may choose to
limits but may not reduce the limits described for the applicable profile. When the
X3D file contains nodes which exceed the limits implemented
by the browser, the results are undefined. The words "optionally supported" in the
browser support column refers only to the display of the item; in particular,
set_ events to ignored inputOutput fields shall still generate corresponding
_changed events. Where latitude is specified in a table
of minimum support requirements for a particular node, full support is
required for other aspects of that node.