STL (STereoLithografy) is a CAD format used widely by rapid prototyping and CAM. The STL files do not describe analytic surfaces, but describe a raw unstructured triangulated surface by the unit normal and vertices of the triangles using a three-dimensional Cartesian coordinate system. No other information like color, texture or other common CAD model attributes are included in this format. The above characteristics of the STL files demand special features when the described geometries are used for meshing. Aircraft are not the most common geometries described by STL format, but there are certain cases which this format can be encountered in the aerospace industry. Below an example of the F-104 conceptual design as described by an STL file.
Some testing and evaluation of STL manipulation techniques in order to prepare the geometry for meshing, took place during the last months closing my latest CFD consulting contract. Manual updates and e-learning material like online text and video tutorials were also part of the work done. Special software for video capturing and text-to-speech conversion were used as part of the video projects.