The document discusses the Initial Graphics Exchange Specification (IGES) format, which is a neutral file format used for CAD data exchange between different software packages. It describes the key components of an IGES file, including the start section, global section, directory entry section, parameter data section, and terminal section. The global section provides metadata about the file. The directory entry and parameter data sections define the geometric entities using parameters. Common entities that can be represented include lines, circles, surfaces of revolution. IGES aims to enable translation between different CAD systems by providing a common format for exchange of geometry and topology data.

1. DATA STANDARD:
IGES
• SHRIVASTAVA HIMANSHU ARJUN KAMINI :14MCD0047
• TONY SEBASTIAN :14MCD0003
(Vellore Institute Of Technology, India)

2. DATA EXCHANGE
• Process of exchanging data from a source to target.
• In CAD system there are many situations where we have to
exchange data from one software package to another.
• We have to translate geometrical data, feature data , assembly
structure, etc.
• In CAD data exchange many software technologies and
methods are involved.

3. FILE TRANSLATION
• One data format is converted to another.
• Important in concurrent engineering.
• Different companies may be using different CAD software.
• One design model may be exported and imported into several
CAD packages before the final file reaches manufacturing.
• Data of one software package may not be compatible with the
other.

4. TYPES OF TRANSLATORS
1. DIRECT TRANSLATORS
Need n(n-1) translators for n softwares.

5. 2. INDIRECT TRANSLATORS
Need 2n translators for n softwares.

6. NEED OF NEUTRAL FILE FORMATS
• It is difficult to enforce the use of a common set of CAD/CAM
tools in different companies.
• Because of the lack of any common set of tools, a common
format for neutral file exchange is needed.
• Usage of neutral standard for transferring information
drastically reduces the requirements for translators.
• Thus cost incurred for data translation is reduced.

7. CAD DATA EXCHANGE USING
NEUTRAL FILES

8. COMMON NEUTRAL FORMATS
• DXF (DRAWING EXCHANGE PROGRAM)
• IGES (INITIAL GRAPHICS EXCHANGE SPECIFICATIONS)
• PARASOLID
• STEP (Standard for the Exchange of Product model data)

9. IGES
• Abbreviation of Initial Graphics Exchange Specification.
• Initiative of USAF-ICAM (United States Air Force – Integrated
Computer Aided Manufacturing).
• It was the first specification for CAD data exchange.
• Got published in 1980 by NBS (National Bureau of Standards).
• The main objective during the development stage of IGES was
the exchange of drafting data like 2D and 3D wireframe
models, text, dimensioning data and a limited class of
surfaces.

10. CAPABILITIES OF CURRENT VERSION
The current version, IGES 5.3, provides the following capabilities:
• Geometry: 2D/3D wireframes, 2D/3D curves and surfaces
• CSG (since version 4.0 in 1988)
• B-Rep (since version 5.1 in 1991)
• Presentation: Drafting entities for technical drawings
• Finite Element Modelling: Elements for FEM systems

11. IGES specification consists of format of the file and product
definition data. The product definition data includes:
1.Geometric Data: entities required to explain the geometry of
the drawings.
2. Topological Data: explains the relationship between different
geometries
The geometric and topological data together gives the
information about geometric shape of the product.
3. Non-Geometrical Data: it can be divided into
• Annotation
• Definition
• Organisation

12. Structure of IGES:
1.Start section
2.Global section
3.Directory entry section
4.Parameter Data Section
5.Terminal section

13. Start Section
• The Start section is a human readable
introduction to the file.
• It is recognize by letter "s" in the IGES file.

14. Global Section
• The Global Section includes properties and descriptions of the
pre-processor and information that are needed by
postprocessor to interpret the file.
• It is recognize by letter "G" in the IGES file.

15. Some of the parameter which are included in this section are:
• 1. The name of IGES file itself.
• 2. Vendor and software version of sending system.
• 3. Date and time of file generation
• 4. Model units
• 5. Name of the author of IGES file and his/her organization.
• 6. Parameter and Records Delimiters.

16. For Example:
1H,,1H;,11Hhook.SLDPRT,30HC:UsersDellDesktophook.IGS,15HSolidworks 2 013 , G 1
15HSolidWorks 2013,32,8,23,308,15,11Hhook.SLDPRT,1.,2,2HMM,50, G 2
0.125, 13H140922.210540, 1E-008, 499990. 4HDell,,11,0,13H140922.210540; G 3
• Field 1: 1H, - defines that “,” is the parameter delimiter
character in the G and D sections (the default is “,”).
• Field 2: 1H; - defines “;” (default) as the record delimiter in G
and D. A record is a group of fields. In the G section there is
only one record.
• Field 3:hook.SLDPRT is the product identification. In this case
this is an IGES file from solidwork where the filename is used
as the product id.

17. 1H,,1H;,11Hhook.SLDPRT,30HC:UsersDellDesktophook.IGS,15HSolidworks 2013, G 1
15HSolidWorks 2013,32,8,23,308,15,11Hhook.SLDPRT,1.,2,2HMM,50, G 2
0.125, 13H140922.210540, 1E-008, 499990. 4HDell,,11,0,13H140922.210540; G 3
• Field 4: C:UsersDellDesktophook.IGS is the file full name.
• Field 5: SolidWorks 2013- IGES identifies the system from
which the IGES file was exported.
• Field 6: Solidworks2013 – identifies the system version.

18. 1H,,1H;,11Hhook.SLDPRT,30HC:UsersDellDesktophook.IGS,15HSolidworks 2013,G
1H,,1H;,11Hhook.SLDPRT,30HC:UsersDellDesktophook.IGS,15HSolidworks 2013, G 1
15HSolidWorks 2013,32,8,23,308,15,11Hhook.SLDPRT,1.,2,2HMM,50, G 2
0.125, 13H140922.210540, 1E-008, 499990. 4HDell,11,0,13H140922.210540; G 3
Field 14: 2-is units used for measuring data. In this example mm
The other units are represented by the following code:
• 1 -inches
• 2 -millimetres
• 4 -feet
• 5 -miles
• 6 -meters
• 7 -kilometre
• 8 -mils(0.001 inches)
• 9 -microns
• 10 -centimetre
• 11 -micro inches
01SolidWorks 2013,32,8,23,308,15,11Hhook.SLDPRT,1.,2,2HMM,50, G 2

19. 1H,,1H;,11Hhook.SLDPRT,30HC:UsersDellDesktophook.IGS,15HSolidworks 2013, G 1
15HSolidWorks 2013,32,8,23,308,15,11Hhook.SLDPRT,1.,2,2HMM,50, G 2
0.125, 13H140922.210540, 1E-008, 499990. 4HDell,,11,0,13H140922.210540; G 3
• Field 19: 1E-008 - Minimum user-intended resolution. Used to
determine if points are “coincident”. With this value, any
manufacturing application can consider coordinate locations
less than this distance apart to be coincident. This field must
always be given a value.

20. Directory Entry Section (DE Section):
• Directory entry section defines the attributes or features of
the entity like line , colour, transformation matrix, etc.
• For every geometric element within an IGES file there is
one Directory Entry. This consists of two 80-character lines
i.e. 20 right-justified fields of 8 characters each.

21. For Example
314 1 0 0 0 00000200D 1
314 0 0 1 0 0D 2
110 2 0 0 0 01010000D 3
110 0 0 1 0 0D 4

22. Parameter Data Section (PD Section):
• The PD section contains the actual data defining each entity in
DE section
• Directory entry and Parameter data are necessary to
completely define an entity. The Parameter Data Section can
be recognizing in IGES file by "P" letter.

23. For Example:
110,0.25,-0.428459771,-0.06,0.25,0.571540229,-0.06; 3P 2
110,0.25,0.,-0.02,0.25,0.071540229,-0.02; 5P 3
120,3,5,0.,6.28318530717959; 7P 4
126,1,1,1,0,1,0,0.,0.,1.,1.,1.,1.,0.,6.283185307,0.,1., 9P 5
6.283185307,0.,0.,1.,0.,0.,1.; 9P 6
110,0.25,0.,-0.02,0.25,0.071540229,-0.02; 11P 7

24. Some example of entity are represented in Parameter Data
Section are:
• 1.Line (entity 110)
A line in IGES file is defined by its end points. The coordinates
of start point and terminate point are included in parameter
data section of this entity.
110,0.25,-0.428459771,-0.06,0.25,0.571540229,-0.06; 3P 2

25. • 2. Circular Arc (entity 100)
To represent a circular arc in modelling space, IGES provides
the information including a new plane (XT YT) in which the
circular lies, the coordinates of centre point, start point, and
terminate point. A new coordinate system (XT, YT, & ZT) is
defined by transferring the original coordinate system (Xo, Yo,
Zo) via a transformation matrix and all coordinates of points
(centre point, start point, and terminate point) related to this
new coordinate system.

26. • Directory Entry Section:
124 10 0 0 0 00000000D 15
124 0 0 4 0 0D 16
100 14 0 0 0 15 01010000D 17
100 0 0 1 0 0D 18
• Parameter Data Section:
100,-0.06,0.25,0.071540229,0.29,0.071540229,0.21,0.071540229; 17P 14

27. • 3.Surface of Revolution:
A surface is created by rotating the generatrix about the axis
of rotation from the start position to the terminal position.
The axis of rotation is a line entity. The generatrix may be a
conic arc, line, circular arc, or composite curve. The angles of
rotation are counter clockwise about the positive direction of
rotation axis.
• For Example:
120,3,5,0.,6.28318530717959; 7P 4

28. Terminal Section:
• The terminal section contains only one record which shows
the number of records in each section. This is used for
checking purpose
• S 1G 3D 262P T 1
Field Columns Section
1 1-8 Start
2 9-16 Global
3 17-24 Directory Entry
4 25-32 Parameter data
5-9 33-72 Not used
10 73-80 Terminate

29. Problem with IGES file import:
• Internal data representing the entities is different than that
required by IGES.
• when the entity is not specifically supported and thus have to
be converted to closet available entity.

30. Import Healing:
• Healing Missing Faces.
• Additional surfaces

31. THANK YOU