Editing IGES

{{Short description|Initial Graphics Exchange Specification}}
[[File:Initial Graphics Exchange Specification Logo.svg|thumb|upright|Logo of the IGES Project from [[National Institute of Standards and Technology|NIST]]]]
The '''Initial Graphics Exchange Specification (IGES)''' is a vendor-neutral [[List of file formats|file format]] that allows the [[CAD data exchange|digital exchange]] of information among [[computer-aided design]] (CAD) systems. It is an ASCII-based textual format.<ref>{{Cite book|last=Schoonmaker|first=Stephen J.|url=https://www.worldcat.org/oclc/54090798|title=The CAD guidebook : a basic manual for understanding and improving computer-aided design|date=2003|publisher=Marcel Dekker|isbn=0-8247-4569-8|location=New York|oclc=54090798}}</ref>{{Rp|page=59}}

The official title of IGES is '''''Digital Representation for Communication of Product Definition Data''''', first published in March, 1980 by the U.S. [[National Bureau of Standards]] as '''NBSIR 80-1978'''.<ref>[https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nbsir80-1978.pdf Initial Graphics Exchange Specification IGES Version 1.0], Roger N. Nagel, Ph.D., Project Manager Walt W. Braithwaite, M.S., Boeing Philip R Kennicott, Ph.D., General Electric, National Bureau of Standards, NBSIR 80-1978, March 1980</ref>  Many documents (like early versions of the [[Defense Standard]]s MIL-PRF-28000<ref>{{cite web |url=http://www.everyspec.com/MIL-PRF/MIL-PRF-010000-29999/MIL-PRF-28000B_NOTICE-1_27385/ |title=MIL-PRF-28000B |work=everyspec.com |date=2011-05-26}}</ref> and MIL-STD-1840<ref>{{cite web |url=http://www.everyspec.com/MIL-STD/MIL-STD-1800-1999/MIL-STD-1840C_4779/ |title=MIL-STD-1840C |work=everyspec.com |date=2011-05-26}}</ref>) referred to it as '''[[American Society of Mechanical Engineers|ASME]] Y14.26M''', the designation of the [[ANSI]] committee that approved IGES Version 1.0.

Using IGES, a CAD user can exchange product data models in the form of [[circuit diagram]]s, [[wire frame model|wireframe]], [[freeform surface modelling|freeform surface]], [[Boundary representation|boundary]] (B-rep) or [[solid modeling]] (CSG) [[Representation (arts)|representations]]. Applications supported by IGES include traditional [[engineering drawing]]s, models for analysis, and other [[manufacturing]] functions.

==History==
IGES was an initiative of the [[United States Air Force]] (USAF) [[Integrated Computer Aided Manufacturing]] (ICAM) project (1976-1984).<ref>{{cite news |url=https://www.pcmag.com/encyclopedia_term/0,,t=&i=44758,00.asp|title=IGES | work=PC Magazine}}</ref>

ICAM sought to develop procedures ([[IDEF]]), processes ([[Group Technology]]), and software ([[CAD/CAM]]) that would integrate all operations in Aerospace manufacturing and thus greatly reduce costs.  Earlier the USAF Manufacturing Technology Program had funded the Automatically Programmed Tools (APT) language for programming Numerically Controlled (NC) machine tools.  To close the data gap between parts design and manufacturing, one of the ICAM goals was to develop CAD software that would automatically generate numerical control programs for the very complex Computer Numerically Controlled (CNC) machine tools used throughout the [[Aerospace]] industry.  A serious issue was the incompatibility of data produced by the many [[Computer-aided design|CAD]] systems in use at the time.  USAF/ICAM called a meeting at the [[National Bureau of Standards]] (now known as [[National Institute of Standards and Technology]] or [[NIST]]) in 1978 to address this issue.  [[Boeing]] offered to sell its CAD translation software to USAF for one United States dollar.  [[USAF]] accepted this offer and contracted NIST to bring together a group of  users and vendors, including Boeing, [[General Electric]], [[Xerox]], [[Computervision]], [[Applicon]] and others to further develop and test this software.  Though it was the practice to begin the name of ICAM developments with the word integrated (for example the IDEFs) believing that there would be rapid development of graphical exchange software, USAF decided that the IGES would be the Initial Graphics Exchange Specification not the Integrated Graphics Exchange Specification.

Since 1988, the [[United States Department of Defense|DoD]] has required that all [[Digital data|digital]] [[product and manufacturing information]] (PMI) for weapons systems contracts (the engineering drawings, circuit diagrams, ''etc''.) be delivered in [[computer file|electronic]] form such as IGES format. As a result, [[CAx]] software vendors who want to market their products to DoD subcontractors and their partners needed to support the import (reading) and export (writing) of IGES format files.

An ANSI standard since 1980, IGES has been used in the [[automotive industry|automotive]], [[aerospace]], and [[shipbuilding]] industries. It has been used for weapons systems from [[Trident (missile)|Trident missile]] [[guidance system]]s to entire [[aircraft carrier]]s. These part models may have to be used years after the vendor of the original design system has gone out of business. IGES files provide a way to access this data decades from now. Today, plugin viewers for [[Web browser]]s allow IGES files created 20 years ago to be viewed from anywhere in the world.<ref>{{cite web |url=http://www.wiz-worx.com/java/figa2.htm |archive-url=https://web.archive.org/web/20160305022829/http://www.wiz-worx.com/java/figa2.htm |url-status=dead |archive-date=2016-03-05 |title=Rotate an IGES part from 1990 with Java}}</ref>

After the initial release of [[ISO 10303|STEP (ISO 10303)]] in 1994, interest in further development of IGES declined, and Version 5.3 (1996) was the last published standard.

==File format==
An IGES file is composed of 80-character [[ASCII]] records, a record length derived from the [[punched card]] era. Text strings are represented in "[[Hollerith constant|Hollerith]]" format, the number of characters in the string, followed by the letter "H", followed by the text string, ''e.g.'', "4HSLOT" (this is the text string format used in early versions of the [[Fortran]] language). Early IGES translators had problems with [[IBM]] [[mainframe computer]]s because the mainframes used [[EBCDIC]] encoding for text, and some EBCDIC-ASCII translators would either substitute the wrong character, or improperly set the [[parity bit]], causing a misread.

Here is a very small IGES file from 1987,<ref>{{cite web |url=http://www.wiz-worx.com/iges5x/misc/slot.shtml |title=MISC - IGES Example File slot |access-date=2010-01-08 |archive-url=https://web.archive.org/web/20100815044620/http://www.wiz-worx.com/iges5x/misc/slot.shtml |archive-date=2010-08-15 |url-status=dead }}</ref> containing only two POINT (Type 116), two CIRCULAR ARC (Type 100), and two LINE (Type 110) entities. It represents a slot, with the points at the centers of the two half-circles that form the ends of the slot, and the two lines that form the sides.

<pre>
                                                                        S      1
1H,,1H;,4HSLOT,37H$1$DUA2:[IGESLIB.BDRAFT.B2I]SLOT.IGS;,                G      1
17HBravo3 BravoDRAFT,31HBravo3->IGES V3.002 (02-Oct-87),32,38,6,38,15,  G      2
4HSLOT,1.,1,4HINCH,8,0.08,13H871006.192927,1.E-06,6.,                   G      3
31HD. A. Harrod, Tel. 313/995-6333,24HAPPLICON - Ann Arbor, MI,4,0;     G      4
     116       1       0       1       0       0       0       0       1D      1
     116       1       5       1       0                               0D      2
     116       2       0       1       0       0       0       0       1D      3
     116       1       5       1       0                               0D      4
     100       3       0       1       0       0       0       0       1D      5
     100       1       2       1       0                               0D      6
     100       4       0       1       0       0       0       0       1D      7
     100       1       2       1       0                               0D      8
     110       5       0       1       0       0       0       0       1D      9
     110       1       3       1       0                               0D     10
     110       6       0       1       0       0       0       0       1D     11
     110       1       3       1       0                               0D     12
116,0.,0.,0.,0,0,0;                                                    1P      1
116,5.,0.,0.,0,0,0;                                                    3P      2
100,0.,0.,0.,0.,1.,0.,-1.,0,0;                                         5P      3
100,0.,5.,0.,5.,-1.,5.,1.,0,0;                                         7P      4
110,0.,-1.,0.,5.,-1.,0.,0,0;                                           9P      5
110,0.,1.,0.,5.,1.,0.,0,0;                                            11P      6
S      1G      4D     12P      6                                        T      1
</pre>The file is divided into 5 sections: '''S'''tart, '''G'''lobal, '''D'''irectory Entry, '''P'''arameter Data, and '''T'''erminate indicated by the characters S, G, D, P, or T in column 73. The characteristics and geometric information for an entity is split between two sections; one in a two record, fixed-length format (the Directory Entry, or DE Section), the other in a multiple record, comma delimited format (the Parameter Data, or PD Section), as can be seen in a more human-readable representation of the file.<ref>{{cite web |url=http://www.wiz-worx.com/iges5x/misc/peek/slot.txt |title=MISC - IGES Example File slot (dump) |access-date=2010-08-16 |archive-url=https://web.archive.org/web/20120926172932/http://www.wiz-worx.com/iges5x/misc/peek/slot.txt |archive-date=2012-09-26 |url-status=dead }}</ref>

When displayed, the user should see two [[yellow]] points (hard to see on a [[white]] background, but most CAD systems use a [[black]] background), one located at the [[Origin (mathematics)|origin]] of model space [0,0,0], two [[red]] circular arcs, and two [[green]] lines.

[[File:slot.gif|center]]

==Foreign-language support==
[[File:fc2001x.gif|thumb|right|200px|fc2001x.igs is an example IGES file that demonstrates Font Code 2001 ('''[[Kanji#History|Kanji]]''')]]
Due to its growing international popularity (several countries, including Australia and the UK, adopted IGES as their own National Standards for PMI interoperability), support was added to the TEXT (Type 212) entity to support the [[ISO/IEC 8859-1|ISO 8859 (Latin-1)]] alphabet for European characters.<ref>{{cite web |url=http://www.wiz-worx.com/iges5x/misc/font3001.shtml |title=MISC - IGES Example File font3001}}</ref>

In the 1990s, IGES added support for the [[JIS encoding]] for [[Kanji]] ([[wikt:漢字|漢字]]) as double-byte characters ([[JIS X 0208|JIS-6226]]), allowing members of the [[Japan Automobile Manufacturers Association]] (JAMA) to exchange part models with their American and European partners without loss of the Kanji text.

The current version of IGES does not support [[Unicode]] 16- or 32-bit character encoding, so Arabic and other scripts (like Thai) cannot be represented.<ref>But see IGES RFC 603, {{cite web |title=MSID Standards Activities |url=http://ts.nist.gov/Standards/IGES/rfc603.cfm |url-status=dead |archive-url=https://archive.today/20120719004148/http://ts.nist.gov/Standards/IGES/rfc603.cfm |archive-date=2012-07-19 |access-date=2011-10-01}} that proposes flagged UTF-8.</ref>

==A recursive standard==
One of the unique features of the IGES standard is that it was the first [[ANSI]] standard to be documented using itself. Since Version 4.0, all of the technical illustrations for the printed version of the standard have been generated from IGES files. The [[electronic publishing]] system ([[LaTeX]]) integrates [[Raster graphics|raster images]] generated from IGES files into the [[PostScript]] sent to the [[laser printer]], so text and images are printed on the same page for subsequent use as [[camera-ready]] copy for commercial publication. Beginning with IGES Version 5.2, this is how the standard was generated, and Version 5.3 (the most recent ANSI-approved version) is available as a [[PDF]] document.<ref>{{cite web |url= http://www.uspro.org/documents/IGES5-3_forDownload.pdf |title= IGES 5.3 (ANSI-1996) |work= US Product Data Association |date= 1996-09-23 |access-date= 2007-07-28 |archive-url= https://web.archive.org/web/20120821190122/http://www.uspro.org/documents/IGES5-3_forDownload.pdf |archive-date= 2012-08-21 |url-status= dead }}</ref>

Many of the illustrations (all of which conform to the Defense Department's MIL-D-28000 Engineering Drawings Subset of IGES) use the entities that they describe, e.g., the illustration of the LEADER (ARROW) ENTITY (Type 214) can be used as a test case for translator implementers, because it contains all 12 arrow head styles defined by the standard. These [[WYSIWYG]] example files can be distinguished by a leading "F" and trailing "X" in the file name (like f214x.igs<ref>{{cite web |url=http://www.wiz-worx.com/iges5x/wysiwyg/f214x.shtml |title=WYSIWYG - IGES Example File f214x |access-date=2010-01-08 |archive-url=https://web.archive.org/web/20100301144417/http://www.wiz-worx.com/iges5x/wysiwyg/f214x.shtml |archive-date=2010-03-01 |url-status=dead }}</ref>), and this library is called the '''IGES X-files''' by members of the IGES [[community]].

Here is one of the example figures, Figure 2 from Appendix A (fmeparte.igs<ref>{{cite web |url=http://www.wiz-worx.com/iges5x/misc/figa2.shtml |title=MISC - IGES Example File figa2 |access-date=2010-01-08 |archive-url=https://web.archive.org/web/20100228145242/http://www.wiz-worx.com/iges5x/misc/figa2.shtml |archive-date=2010-02-28 |url-status=dead }}</ref>), that has appeared in every version of IGES since Version 3.0. It uses linear, angular, and ordinate dimension entities, as well as examples of both [[Conic section|circular and conic arcs]]. It is usually the first part used when testing an IGES translator, because the standard has a picture of what it should look like.

[[File:figa2.gif|center|500px]]

==See also==
{{Clear}}

* [[ISO 10303-21]] or STEP-file, an ISO standardized format

==References==
{{Reflist|30em}}
;Notes
*{{Citation |first1=Roger N. |last1= Nagel |first2=Walt W. |last2=Braithwaite |first3=Philip R. |last3=Kennicott |title=Initial Graphics Exchange Specification IGES, Version 1.0 |id=NBSIR 80-1978 |publisher=National Bureau of Standards |location= Washington DC |year=1980 |ref=CITEREFIGES1980 }}
* 1982 https://books.google.com/books/about/Digital_representation_for_communication.html?id=5LDgAAAAMAAJ
* 1990 https://books.google.com/books/about/Digital_representation_for_communication.html?id=tyFZAAAAYAAJ
*{{Citation |title=Digital Representation for Communication of Product Definition Data: IGES 5.2 (Initial Graphics Exchange Specification Version 5.2) |date=November 1993 |publisher=US Product Data Association |isbn=978-1-88538900-8 }}
*{{Citation |author=IGES/PDES Organization |title= Initial Graphics Exchange Specification: IGES 5.3 |publisher=U.S. Product Data Association |date=September 23, 1996 |location=N. Charleston, SC |archive-url=https://web.archive.org/web/20120821190122/http://www.uspro.org/documents/IGES5-3_forDownload.pdf |archive-date=August 21, 2012 |url=http://www.uspro.org/documents/IGES5-3_forDownload.pdf |quote=Formerly an ANSI Standard September 23, 1996 &ndash; September 2006}}
*{{Citation |author=IGES/PDES Organization |title=The Initial Graphics Exchange Specification (IGES) Version 5.x (Draft) |date=June 28, 2006 |publisher=IGES/PDES Organization }}. Baseline version was January 12, 1999.
*{{Citation |author=IGES/PDES Organization |title=The Initial Graphics Exchange Specification (IGES) Version 6.0 (Draft) |date=November 30, 2001 }}. Baseline version was January 5, 1998.

==External links==
* {{cite web |url=http://ts.nist.gov/standards/iges/ |title=A General Description of IGES |work=[[National Institute of Standards and Technology|nist.gov]] |url-status=dead |archive-url=https://web.archive.org/web/20120417202421/http://www.nist.gov/el/msid/standards.cfm |archive-date=2012-04-17 }}

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