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FIPS PUB 177-1
Supersedes FIPS PUB 177
1992 November 30
Federal Information
Processing Standards Publication 177-1
1996 April 23
Announcing the Standard for
INITIAL GRAPHICS EXCHANGE SPECIFICATION
(IGES)
Federal Information Processing Standards Publications (FIPS PUBS)
are issued by the National Institute of Standards and Technology after
approval by the Secretary of Commerce pursuant to Section 111(d) of the
Federal Property and Administrative Services Act of 1949, as amended by the
Computer Security Act of 1987, Public Law 100-235.
1. Name of Standard. Initial Graphics Exchange Specification
(IGES) (FIPS PUB 177-1).
2. Category of Standard. Software Standard; Graphics and
Information Interchange.
3. Explanation. This publication is a revision of the FIPS PUB 177
and supersedes FIPS PUB 177 in its entirety. It provides a
substantial, upward-compatible enhancement of IGES Version 4.0.
FIPS PUB 177-1 specifies new conformance requirements, the addition
and use of application protocols (APs), and increased enhancement,
correction, and clarification of the existing specification. It
does not contain any new requirements that would make an existing
conforming implementation nonconforming.
FIPS PUB 177-1 adopts the American National Standard Digital
Representation for Communication of Product Definition Data,
ANSI/US PRO/IPO (United States Product Data Association/IGES PDES
Organization)-100-1993, Version 5.2, and the specified application
protocols. FIPS PUB 177-1 addresses IGES implementation and data
file acquisition, interpretation, and conformance.
The purpose of the FIPS for IGES is to enable the compatible
exchange of product definition data used by dissimilar computer-
aided design and computer-aided manufacturing (CAD/CAM) systems.
Utilizing a neutral database format the IGES processor can create
or translate two-dimensional (2-D) or three-dimensional (3-D)
vector-based digital product model data. The standard specifies
file structure and syntactical definition, and defines the
representation of geometric, topological, and nongeometric product
definition data. The exact specification is in Section 10 of this
standard.
4. Approving Authority. Secretary of Commerce.
5. Maintenance Agency. U.S. Department of Commerce, National
Institute of Standards and Technology (NIST), Computer Systems
Laboratory (CSL).
6. Cross Index.
- a. American National Standard Digital Representation for
Communication of Product Definition Data, ANSI/US PRO/IPO-100-1993,
Version 5.2.
- b. American Society of Mechanical Engineers/American National
Standards Institute (ASME/ANSI) Y14.26M-1989, Digital
Representation for Communication of Product Definition Data, IGES
Version 4.0.
- c. MIL-D-28000A, Continuous Acquisition and Life-Cycle
Support Specification, Digital Representation for Communication of
Product Definition Data: IGES Application Subsets and IGES
Application Protocols, February 10, 1992.
- d. American National Standard, 3-D Piping IGES Application
Protocol, ANSI/US PRO/IPO-110-1994.
- e. IGES Layered Electrical Product Application Protocol,
Committee Draft SAND94-2375, December 1, 1994.
7. Related Documents.
- a. Federal Information Resources Management Regulations
(FIRMR) subpart 201.20.303, Standards, and subpart 201.39.1002,
Federal Standards.
- b. Federal ADP and Telecommunications Standards Index, U.S.
General Services Administration, Information Technology Management
Service, October 1994 (updated periodically).
- c. FIPS PUB 29-3, Interpretation Procedures for Federal
Information Processing Standards for Software.
- d. NISTIR 4379, IGES Technical Illustrations Application
Guide.
- e. NISTIR 4600, IGES 5.0 Recommended Practices Guide.
- f. NISTIR 5541, Initial Graphics Exchange Specification
(IGES): Procedures for the NIST IGES Validation Test Service.
- g. MIL-T-31000, General Specification for Technical Data
Packages.
8. Objectives. Federal standards for electronic interchange
permit Federal departments and agencies to exercise more effective
control over the production, management, and use of the
government's information resources. The primary objectives
specific to IGES are to:
- - Reduce the overall life-cycle cost for digital systems by
establishing a common exchange format that allows for the
transfer of product definition data across organizational
boundaries and independent of any particular CAD/CAM
system.
- - Exchange digital representations of product definition
data in various forms: illustrations, 2-D drawings, 3-D
edge-vertex models, surface models, solid models, and
complete product models.
- - Provide CAD/CAM implementation manufacturers with a
guideline for identifying useful combinations of product
definition data capabilities in any CAD/CAM system.
- - Specify Application Protocols that can be used by Federal
departments and agencies to support the exchange of
product data when applicable.
9. Applicability.
9.1 This FIPS for IGES is intended for the computer-
interpretable representation and exchange of CAD/CAM product
definition data among applications and programs that are either
developed or acquired for government use. Each CAD/CAM system
acquired or developed by a Federal agency shall include an IGES
preprocessor and IGES postprocessor capability. FIPS for IGES is
designed to support the exchange of 2-D or 3-D product definition
data with rich attribute information. It provides a data format
for describing product design and manufacturing information that
has been created and stored in a computer-readable, device
independent form.
9.2 The FIPS for IGES shall be used when one or more of the
following situations exist:
- - The product definition application or program is under
constant review, and changes may result frequently.
- - It is anticipated that the life of the data files will be
longer than the life of the presently utilized CAD/CAM
system.
- - The application is being designed centrally for a
decentralized system that may employ computers of
different makes and models and different CAD/CAM devices.
- - The product definition application may run on equipment
other than that on which it was developed.
- - The product definition data is to be used and maintained
by other than the original designer.
- - The product definition data is or is likely to be used by
organizations outside the Federal Government.
- - It is desired to have the design understood by multiple
people, groups, or organizations.
9.3 For layered electrical product technology, three
dimensional piping, and engineering drawing applications, the use
of the appropriate application protocol or subset (as described
below) is required for implementation of this FIPS IGES.
An AP or subset provides a means to improve the fidelity of the
product data exchanged. APs are developed by domain experts for
the purpose of defining the processes, information flows, and
functional requirements of an application. An AP defines the
scope, context, information requirements, representation of the
application information, and conformance requirements. Initial
release of this FIPS for IGES publication includes two application
protocols and one application subset.
- - Layered Electrical Product (LEP) Application Protocol:
The LEP AP is used for the transference of 2-D electrical
and electro-mechanical product models. This AP is
required for layered electrical products technology
applications, including specification control drawings,
circuitry, fabrication and final assembly of a layered
product system.
- - 3-D Piping Application Protocol: The 3-D Piping AP is
used for the exchange of models from one piping modeling
application to another. This AP is required for 3-D
piping and related equipment models, including the
fabrication and assembly of piping systems (e.g. pipe,
pipe fittings, attached equipment, piping supports, and
insulation).
- - Engineering Drawing (Class II) Subset (MIL-D-28000A):
The Class II subset is used for the exchange of the
drawing model; including geometric and annotation
entities, attributes such as color and line fonts, and
organization information such as levels and subfigures.
This subset is required for the exchange of engineering
drawings and product data following MIL-T-31000 (General
Specification for Technical Data Packages).
10. Specifications. This FIPS adopts ANSI/US PRO/IPO-100-1993
and the specified application protocols: Layered Electrical Product (LEP)
Application Protocol; 3-D Piping Application Protocol; and Engineering
Drawing (Class II) Subset (MIL-D-28000A). The ANSI/US
PRO/IPO-100-1993 standard for IGES, defines the communications file
structure and format (i.e., a file of entities), language format, and the
representation of product definition data.
New entities and constructs are added with each revision and are
upwardly compatible. Thus, a processor conforming to IGES Version
5.2 would be able to read and process an IGES Version 4.0 file, but
the converse may not be true. The capabilities brought to the IGES
user implementing the IGES Version 5.2 standard are:
- - a new character set for the European Community;
- - additional properties to the attribute table for
Architecture/Engineering/Construction (AEC);
- - the addition of a new form of the drawing entity; and
- - the addition of a new class of entity use, termed
construction information.
Conformance Requirements. Conformance is mandatory for this
standard and is applicable to all Federal department and agency
procurements. Conforming data files and processors must adhere to
all the rules appropriate to specific features, such as entities,
defined within ANSI/US PRO/IPO-100-1993 and any of the specified
application protocols. Vendors of processors claiming conformance
to this standard shall complete documentation which accurately
indicates the processor's support of, and mapping between, native
and IGES entities.
A conforming preprocessor shall create conforming IGES data files
which represent the native database which was input to the
preprocessor. File content shall represent the native entities
according to the vendor's completed documentation. It is desirable
and recommended that the preprocessor report on any native feature
or entity which has not been written to the IGES data file.
A conforming postprocessor shall translate conforming IGES data
files into the native database form of a specific CAD/CAM system.
It shall convert each supported entity into native constructs,
which preserve the functionality and match the geometry,
attributes, and relationships of the IGES entity in the file. It
is desirable and recommended that the postprocessor report on any
IGES entities or features which have been discarded.
Any visual presentation produced by the processor shall accurately
and correctly represent the IGES constructs contained in the data
file and specified by ANSI/US PRO/IPO-100-1993 and, if applicable,
the AP or subset. For example, the display of a design which is
filled with a pattern of lines as indicated by the pattern code of
the Sectioned Area Entity (type 230) shall resemble the predefined
definitions illustrated in the ANSI/US PRO/IPO-100-1993
specification.
Conformance Rules for Application Protocols and Subsets. An
application protocol or subset which claims conformance to this
standard, must satisfy the following rule:
- - An implementation conforming to an AP shall satisfy the
conformance requirements specified in the AP as well as
the conformance requirements in the ANSI/US PRO/IPO-100-
1993 specification.
11. Implementation. The implementation of this standard involves
four areas of consideration: effective date, acquisition,
interpretation, and validation.
11.1 Effective Date. This publication is effective six (6)
months after date of publication upon final announcement in the
Federal Register. A transition period of twelve (12) months,
beginning on the effective date, allows industry to produce IGES
implementations and data files conforming to this standard.
Agencies are encouraged to use this standard for solicitation
proposals during the transition period. This standard is mandatory
for use in all solicitation proposals for IGES data files and
implementations (i.e., computer-aided design and manufacturing
systems) acquired twelve (12) months after the effective date.
11.2 Acquisition of IGES Implementations and Data Files.
Conformance to this standard should be considered whether the
CAD/CAM systems are developed internally, acquired as part of a
system procurement, acquired by separate procurement, used under a
leasing agreement, or specified for use in contracts for
programming services. Recommended terminology for procurement of
FIPS IGES is contained in the U.S. General Services Administration
publication Federal ADP and Telecommunications Standards Index,
Chapter 5, Part 1.
11.3 Interpretation FIPS IGES. Resolutions of questions
regarding this standard will be provided by NIST. Procedures for
interpretations are specified in FIPS PUB 29-3. All questions
concerning the specifications and content should be addressed to:
Director
Computer Systems Laboratory
ATTN: FIPS IGES Interpretation
National Institute of Standards and Technology
Gaithersburg, MD 20899
11.4 Validation of IGES Implementations. Implementations of
FIPS for IGES shall be validated in accordance with the NIST
Computer Systems Laboratory (CSL) validation procedures for FIPS
for IGES, NISTIR 5541, Procedures for the NIST IGES Validation Test
Service. Recommended procurement terminology for validation of
FIPS for IGES is contained in the U.S. General Services
Administration publication Federal ADP and Telecommunications
Standards Index, Chapter 5, Part 2. This GSA publication provides
terminology for three validation options: Delayed Validation,
Prior Validation Testing, and Prior Validation. The agency shall
select the appropriate validation option and shall specify
appropriate time frames for validation and correction of
nonconformities. The agency is advised to refer to the NIST
publication Validated Products List for information about the
validation status of IGES products. This information may be used
to specify validation time frames that are not unduly restrictive
of competition.
Implementations shall be evaluated using the NIST IGES Test Suite.
The NIST IGES Test Suite was first released in October 1994 to
assist users and vendors determine compliance with FIPS PUB 177
and/or MIL-D-28000, Class II subset. The results of validation
testing by the NIST IGES Validation Test Service are published on
a quarterly basis in the Validated Products List, available from
the National Technical Information Service (NTIS).
Current information about the NIST IGES Validation Test Service and
validation procedures for FIPS for IGES is available from:
National Institute of Standards and Technology
Computer Systems Laboratory
Graphics Software Group, IGES Test Service
Building 225, Room A266
Gaithersburg, MD 20899
(301) 975-3265
12. Waivers.
Under certain exceptional circumstances, the heads of Federal
departments and agencies may approve waivers to Federal Information
Processing Standards (FIPS). The head of such agency may
redelegate such authority only to a senior official designated
pursuant to section 3506(b) of Title 44, U.S. Code. Waivers shall
be granted only when:
- a. Compliance with a standard would adversely affect the
accomplishment of the mission of an operator of a Federal computer
system, or
- b. Cause a major adverse financial impact on the operator
which is not offset by Governmentwide savings.
Agency heads may act upon a written waiver request containing the
information detailed above. Agency heads may also act without a
written waiver request when they determine that conditions for
meeting the standard cannot be met. Agency heads may approve
waivers only by a written decision which explains the basis on
which the agency head made the required finding(s). A copy of each
such decision, with procurement sensitive or classified portions
clearly identified, shall be sent to: National Institute of
Standards and Technology; ATTN: FIPS Waiver Decisions, Technology
Building, Room B-154; Gaithersburg, MD 20899.
In addition, notice of each waiver granted and each delegation of
authority to approve waivers shall be sent promptly to the
Committee on Government Operations of the House of Representatives
and the Committee on Governmental Affairs of the Senate and shall
be published promptly in the Federal Register.
When the determination on a waiver applies to the procurement of
equipment and/or services, a notice of the waiver determination
must be published in the Commerce Business Daily as a part of the
notice of solicitation for offers of an acquisition or, if the
waiver determination is made after that notice is published, by
amendment to such notice.
A copy of the waiver, any supporting documents, the document
approving the waiver and any supporting and accompanying documents,
with such deletions as the agency is authorized and decides to make
under 5 U.S.C. Sec. 552(b), shall be part of the procurement
documentation and retained by the agency.
13. Where to Obtain Copies. Copies of this publication are for
sale by the National Technical Information Service, U.S. Department
of Commerce, Springfield, VA 22161. (Sale of the included
specifications document is by arrangement with the National
Computer Graphics Association.) When ordering, refer to Federal
Information Processing Standards Publication 177-1 (FIPSPUB177-1),
and title. Payment may be made by check, money order, or NTIS
deposit account.