STL, abbreviation for stereolithrography, is an interchangeable file format that represents 3-dimensional surface geometry. The file format finds its usage in several fields such as rapid prototyping, 3D printing and computer-aided manufacturing. It represents a surface as a series of small triangles, known as facets, where each facet is described by a perpendicular direction and three points representing the vertices of the triangle.
PPS, PowerPoint Slide Show, files are created using Microsoft PowerPoint for Slide Show purpose. PPS file reading and creation is supported by Microsoft PowerPoint 97-2003. The more latest version of this file format is PPSX which is based on Office OpenXML standards. PPS files can still be read by latest versions of Microsoft PowerPoint, but newly created files can only be saved in PPSX file format. When a PPS file is shared with another user and opened, it starts as Powerpoint show unlike PPT file which opens in editable mode.
You can also convert STL into many other file formats. Please see the complete list below.