IGES File Format Specification: Section G
G (Global) SectionThe G section contains information about the software that has created the IGES file.
1H,,1H;,10H1POINT.IGS,81HC:/GEODIGM/CUSTOMERS/XXXXXXX/vehicle-XYZ/SURFDAG 1 TA/bumper-project2/iges/surf01.igs,21HICEM LTD. - ICEM IGES,8H18.104.22.168, G 2 32,8,23,11,52,10HSURF01.IGS,1.,2,2HMM,4,0.7,15H20110308.101309, G 3 0.1000000000E-003,4747.868164,,,11,,,; G 4
Character 73 here is G, denoting the G section. The G section line numbers are right-justified and are shown at the end of each line (characters 74-80).
Notice that in many places there are comma-delimited strings such as 10HSURF01.IGS
Here the number 10 in front of the letter H defines the number of characters that appear after the H. i.e. in this case 10. So the string reads "SURF01.IGS" which in this example is the name of the IGES file.
The comma-delimited strings are referred to as fields. By default these fields are delimited by commas but this is always the case. The first field can be used to specify other delimiters. I don't know, but I suspect, that virtually all systems would use the default comma delimiter - after all, why would anyone want to change this?
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: 10HSURF01.IGS – SURF01.igs is the product identification. In this case this is an IGES file from ICEM Surf where the filename is used as the product id.
Field 4: 81H/GEODIGM/CUSTOMERS/XXXXXXX/vehicle-XYZ/SURFDATA/bumper-project2/iges/surf01.igs is the full file name.
Field 5: 21HICEM LTD. - ICEM IGES identifies the system from which the IGES file was exported, in this case ICEM Surf.
Field 6: 8H22.214.171.124 – identifies the system version. In this case ICEM 126.96.36.199
Field 7: 32 – is the number of binary bits used for integer representation.
Field 8: 8 – is the maximum power of 10 which can be represented by a single precision number in the sending system.
Field 9: 23 – is the maximum no. of significant decimal digits.
Field 10: 11 – is the double precision magnitude.
Field 11: 52 – is the double precision significance.
Field 12: 10HSURF01.IGS is an identifier for the receiving system.
Field 13: 1. is the model space scale.
Field 14: 1 would define that the model units were inches, 2 would signify millimeters.
|3||see field 15 below|
|8||mils (0.001 inches)|
Field 15: 2HMM – this is only used by IGES if the field 14 = 3. Otherwise it is not necessary but useful for human readability
Field 16: 4 – max. number of line weight graduations
Field 17: 0.7 – width of maximum line weight in model units
Field 18: 15H20110308.101309 – date and time stamp 15HYYYYMMDD.HHNNSS or 13HYYMMDD.HHNNSS
Field 19: 0.1000000000E-003 - Minimum user-intended resolution. Used to determine if points are “coincident”
Field 20: 4747.868164 – approx. largest coordinate value
Field 21: Author, default is NULL
Field 22: Organisation, default is NULL
Field 23: 11 - IGES version number. 11 represents 5.3
|2||ANSI Y14.26M - 1981||ANSI81|
|5||ASME/ANSI Y14.26M - 1987||ASME87|
|7||ASME Y14.26M - 1989||ASME89|
Field 24: Drafting standard, if any. In this case it has been left blank i.e. NULL. Can be 0-7:
Field 25: Date and time that model was created/modified. In this example this is left blank.
Field 26: Application protocol. Again, blank in this example.