| Extension | PDF |
| Full Name | Portable Document Format |
| Type | Document |
| Mime Type | application/pdf |
| Format | Binary |
PDF documents have been around for many years, becoming the standard format for storing and transmitting documents with rich content such as formatted text, images, tables, and other complex formatting. The format is still under development, with new features being added with each revision.
One of the reasons for its widespread adoption is its ability to store all the required document components, especially fonts, within a single file, allowing the document to be rendered equally on different platforms and devices.
PDF documents are read-only, unless opened within Adobe's own editing software. Support for importing and converting to and from the PDF format is widely supported by document editing software.
The STL, or Standard Triangle Language, file format has been around since the '80s and is supported by most modern 3D modeling 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 flavors: 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.
