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.
Files with .OTP extension represent presentation template files created by applications in OASIS OpenDocument standard format. The contents of such a file include presentation information in the form of slides with text, images, shapes, multimedia content, transition effects and other slide elements. These template files are used for creating new presentations quickly based on the styling information stored in the template itself. OTP files can be created and saved with several different applications such as Impress that comes with OpenOffice suite and Microsoft PowerPoint. The OTP file format is similar to Microsoft PowerPoint template files .POT and .POTX.
You can also convert STL into many other file formats. Please see the complete list below.