STL Files

What is an STL File?

“.STL” is a common file format used in 3D printing. STL stands for STereoLithography and contains data of a 3D object’s layout, generated by computer-aided design (CAD) software. Being one of the most widely used file formats for 3D printing, STL is found in use by hobbyists and professionals alike. STL files are important for 3D printing, as it contains the 3D model which will be printed.

How do STL Files Work?

Objects in STL files are made up of connected triangles, making up the object’s surface. The higher the model’s resolution, the more triangles it must have. Though this will make the objects within appear higher quality, the file size increases with the number of triangles.

Why use STL Files?

In short, STL files are simple. You can make incredibly complex designs using only simple triangles.

STL files are powerful as they are scalable. This means you can make any 3D model in an STL bigger and smaller without losing much quality. They are also universal, working with virtually all 3D printers and CAD software. This also makes them easy to learn and then use.

Can I print any STL?

While all STL files you obtain here at Printable Scenery are 3D printer ready, this is not the case for all STL files elsewhere on the web. Think of it this way: a word document is designed to hold words and sentences. If the data within is just gibberish, you won’t be able to understand it. In the same sense, data within an STL file must meet certain criteria for a printer to properly understand and output it.

3D models which are suitable for 3D printing must have a minimum wall thickness and be “watertight in their design, with all surfaces properly connecting.

What’s more is that models which have overhanging or free-standing elements at more than a 35 degree angle require supports to print. Without supports, the printer will attempt to print where it should, but filament will warp or simply fall to whatever’s below. In this case, before you print any STL files you find online it’s best to give them a look over in 3D modeling software. This will save you time and money with failed prints.

How do I print an STL?

For 3D printing STL files, you will need some additional software. Known as slicers, this software will convert digital 3D models into printing instructions.

A slicer will reduce the model into horizontal layers based on your settings. It will also calculate how much filament will be used, and the time taken to complete the print.

The slicer then outputs a G-code file, which is the file format you then upload to your 3D printer.

How do I open and edit an STL file?

If you just want to open and view and STL file, there are lots of file viewers available. These come as either online applications or desktop software to install on your computer.

Otherwise for editing purposes, there is also software available. This software will allow you to change any qualities of a model to your liking, and even convert to other file formats. Editing may be worthwhile for some Printable Scenery models in particular, as they may be too large to suit your 3D printer. For reference on what to look for in a 3D printer, refer to our article on Buying a 3D Printer.


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