| Extension | IGS |
| Full Name | Initial Graphics Exchange Specification |
| Type | CAD |
| Mime Type | application/iges |
| Format | Binary |
The IGS file format is a Computer Aided Design (CAD) file format originally developed in the 1980s. With the many CAD applications available at the time, all using their own file format, the IGS format was created to be a standard format to exchange data between CAD applications.
All the common features of CAD files can be represented using the IGS format, including basic elements such as lines, curves, text, and other shapes, along with their visual properties such as their colour and other metadata.
The IGS format has since been superseded by other, more capable formats, such as STEP; however, IGS files can still be opened with some modern CAD applications. We also have tools for converting IGS files to other CAD and 3D model formats.
The STL, or Standard Triangle Language, file format has been around since the '80s and is supported by most modern 3D modelling applications. In particular, the STL format has become something of a standard format within the area of 3D printing, despite the rise of more modern formats such as 3MF.
STL files come in two flavours: binary or text format. The text format is human-readable, making it easy to perform manual edits, but can lead to very large file sizes. As you can imagine, the binary format is much more compact and represents the majority of the STL files you are likely to encounter.
The format itself is very simple; the 3D model is represented by a sequential list of triangles, with each triangle defined with 3 points consisting of their X, Y, and Z positions, along with an additional vector that contains the face normal (the direction the face is pointing). There is an additional attribute block for each triangle; however, this is largely unused and thus unsupported.
