For example, the string IGES would be 4HIGES. Note that the strings are expressed in Hollerith format, meaning that every string has the number of characters it contains followed by an H directly preceding it. It also must be present in the file and end with the G000000# format. The global section contains preprocessor data. There must be at least 1 line of the Start section. The start field contains human readable descriptions of the file, and my have any characters in columns 1-72, with the line ending with the section header and section line number. The Start and Global sections contain basic information about the name of the file and its source, the delimiters for the Parameter Data section, the author of the file, and other general information. The Data Entry and Parameter Data sections are commonly abbreviated DE and PD, respectively. Those sections are Start (S), Global (G), Data Entry (D), Parameter Data (P), and Terminate (T) sections. As explained in the Wikipedia article on IGES, the file is split into five sections, denoted by the specific upper case letter in the 73rd column. The file is an ASCII text based format, having each line be exactly 80 characters long. It can be used to represent both Boundary-Representation (B-Rep) and Constructive Solid Geometry (CSG) geometries, as well as two dimensional CAD diagrams. It is an older specification, and was most recently published as version 6 here. The Initial Graphics Exchange Specification (IGES) outlines a file format for the transfer of geometry data and CAD models. 2.3.41 Singular Subfigure Instance (Type 408).2.3.36 Right Circular Conical Surface (Type 194).2.3.35 Right Circular Cylindrical Surface (Type 192).2.3.33 Manifold Solid B-Rep Object (Type 186).2.3.30 Solid of Linear Extrusion (Type 164).2.3.25 Right Circular Cylinder (Type 154).