An Intro to STL Files

As 3D printing becomes increasingly accessible, so will the technology that makes it all possible. Already, companies from a myriad of backgrounds are tracking 3D printing organizations like Pinshape and YouMagine, to get a glimpse of how this amazing technology works. As should you, because once it becomes more accessible, you will want to know a few things about it. Like STL files, known as “Standard Triangle Language” or “Stereolithography”, the most necessary component of all. 

 STL files take an image from a CAD model, which is used to visually create a virtual design; STL files also provide a reference point from which that object is printed.

Two Types of STL Files

There are two types of these files: ASCII and binary. While binary files are much smaller and used more often, ASCII files are easier to tweak and modify over time. In terms of functionality, these files are often used to the same effect.

Think virtual cookie cutter. These files essentially define an objects parameter and overall shape by using coordinates to transfer the data required to print the dimensions of each object. 

 It’s possible that STL files are as important as the CAD model itself, since they act as the primary medium, transferring designs from a virtual concept to a physical object.

STL Files are Easily Found Online

They are also readily accessible online. In fact, people are now sharing STL files on the web, and these files can be downloaded right to your computer. If you’re interested in finding this out for yourself, Thingiverse is a resourceful place to start. 

It’s Made of Triangles, Lots of Primitive Triangles

 The significance behind STL files is geometry, namely the Cartesian coordinate system. Using three-dimensional triangles, STL files act as virtual grids, each containing a collection of facets that act as a boundary between the interior and the exterior of each object. These facets are used  much like a ruler to satisfy the vertex-to vertex rule: all facets must share two sides with its adjacent triangle to create a positive octant; and all coordinates must be positive to meet this requirement. 

 Think about it? To be transformed  into a solid object, STL files must have connecting sides with corresponding units. If this weren’t the case, there would be no way to form those objects. It would be as if you were trying to connect two parts of a bridge with different sized beams. 

As Pythagoras always said

 As Pythagoras always said, “there is geometry in the humming of the strings, there is music in the spacing of the spheres.” And now there is geometry in the virtual transference of material objects. After all, geometry is the underlining theory behind STL files.

The only way to upload triangulated geometry from a computer-aided manufacturing system (CAM) to a rapid prototyping machine (RP) is through a STL file [is that true?]. To do that, you need coordinates with corresponding dimensions. The end result is truly remarkable. The process of turning virtual materiality into a physical reality becomes nothing more than basic geometry.  Which leads me to believe. If Pythagoras were still alive, he would probably buy himself a 3D printer.

Markforged Team
September 16, 2015
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