STL (stereolithography) is a file format native to the stereolithography CAD software created by 3D Systems. It is widely used for 3D printing and is supported by many 3D printers. An STL file describes only the surface geometry of a three-dimensional object without any representation of color, texture or other common CAD model attributes.

STL files contain polygonal data, which represents the surfaces of 3D objects using triangles. The file format is simple and easy to use, making it a popular choice for 3D printing and computer-aided design (CAD) applications.

To work with STL files, you'll need an STL reader. There are many software programs and online tools available for reading and viewing STL files. These STL readers allow you to open and inspect the contents of an STL file, making it easier to prepare the file for 3D printing or further CAD modeling.

Using an STL reader, you can check the integrity of the file, identify any potential issues with the 3D model, and make necessary modifications before sending it to a 3D printer. STL readers also provide visualization tools to view the 3D model from different angles, measure dimensions, and inspect the overall quality of the geometry.

Many 3D modeling and CAD software programs include built-in STL readers, making it convenient to work with STL files within the same environment where you create and modify 3D models. Some popular CAD programs with STL reading capabilities include AutoCAD, Fusion 360, SolidWorks, and Tinkercad.

In addition to desktop software, there are also online STL viewers that allow you to upload and view STL files directly in a web browser. These web-based STL readers are convenient for quick inspections and sharing 3D models with others without the need for specialized software installation.

When choosing an STL reader, consider the specific features and tools that best suit your workflow for 3D modeling and 3D printing. Look for capabilities such as mesh repair, slicing previews, unit conversion, and export options to ensure compatibility with your 3D printing setup.

In conclusion, STL files are essential for 3D modeling and 3D printing, and having a reliable STL reader is crucial for working with these files. Whether you're a professional 3D designer or a hobbyist exploring the world of 3D printing, understanding how to use an STL reader will help you create and print high-quality 3D models with confidence and ease.