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What is .STL File Format – Its Applications, Pros and Cons?

The world keeps evolving and so is technology. The 3D printing industry is a versatile one that keeps experiencing growth overtime. The .STL file is a common file format in the 3D industry. For lovers of 3D models, this file stores and translates complicated designs to printers and software.

.STL File Format – What is it?

The .STL file format is widely used for CAD design and 3D printing. STL stands for stereolithography, which is a 3D printing technology. Also, it is otherwise known as Standard Tessellation Language or Standard Triangle Language.

Every file comprises a series of connected triangles that explains the 3D model’s surface geometry. Also, more complicated design comprises more triangles. It is easy to identify an STL image by the .STL file extension. Also, the lack of texture and color is another way to identify this file.

The 3D systems created the .STL file format in 1987. This file format was part of a STL printing technology for 3D printers. Since the creation of the STL file format, it has been the standard for 3D printing. There haven’t been much changes to this technology. Also, it still utilizes triangular tessellation to design the geometric surface of a model. Therefore it stores information about every triangle. This includes coordinates of each different vertices.

The .STL file describes both binary representations and ASCII. However, binary files are more compact. Therefore, they are more common. There are several software packages that support the .STL file format. This file specifies an unstructured surface by the vertices of the triangles.

What are the Applications of .STL Files

.STL file format transmits the geometry of a 3D design and brings CAD designs to life. This file format is widely used for:

Rapid prototyping

.STL file format enhances the creation of scale models for quick prototyping. Therefore, .STL file format design a part and then prints out to test the part in various scenarios. This file format does this before finalizing the design.

3D printing

3D printing is an approach to industrial production. With the help of .STL file format, designers print 3D design in layers. This will help to create stronger and lighter parts.

Computer-aided manufacturing

Advantages and Disadvantages of .STL File Formats

.STL file formats feature several advantages. However, this file format has its disadvantages. Therefore, it isn’t always ideal for your needs.

Advantages of .STL files

  • Almost all 3D printers can utilize the .STL file format. This is because it is widely recognized as the standard for 3D printing. Therefore, it is a great choice for printing and designing 3D objects.
  • Also, the .STL file can create various objects. Irrespective of the shape, this file format can design an accurate model. It can create objects like plant pots and drones.
  • .STL files are faster at processing despite their small size. This is because of the absence of texture and color. Therefore, this file format is a great option when printing an object or model in a single material and color.

Disadvantages of .STL Files

  • Metadata can’t be stored on this file. For instance, it can’t store details like location and copyright. These details are very crucial to publishing.
  • .STL file has limited capabilities in terms of texture and color. Therefore, it is ideal for designing prototypes instead of the final product.

How to Open an .STL File

There are several ways you can open an .STL file. However, this depends on the operating system.

On Windows

Ensure you have installed the 3D Viewer appl. After installing it, right-click on your file and choose “Open With.” After this, select the 3D viewer. Then the 3D model image will display

On Mac

There are various online tools you can use to view .STL files in a browser. Also, you can download the STL viewer application to preview designs.

Steps to Create and Edit .STL File

Follow these steps to create .STL file for a 3D model using Adobe Photoshop

  • Create a new document and use the Layers tool to create your design
  • Click on the Window tab on the top and choose Workspace and 3D
  • Select your design and 3D extrusion on the 3D tab
  • Adjust the depth and scale of your model
  • Choose the 3D Print Settings and click on Scene to display the full design. Do this if you are exporting the file.
  • Also, set the Printer dropdowns to .STL file and set the “Print To” to Local
  • Save the file by Clicking on Export

How .STL File Format Stores a Model

The .STL file format encodes the surface geometry of an object. Also, it encodes this data with the help of a concept known as tessellation.

What is Tessellation?

This refers to tiling a surface with geometric shape(s) in which there are no gaps or overlaps. An example of this concept is a tile wall or fall. Also, tessellation can comprise complicated shapes or simple geometric shapes.

For instance, if there is a 3D cube, you can cover it by 12 triangles. You can cover a 3D sphere by small triangles.

Rules for the .STL File Format

There are rules for tessellation and storing data in .STL file format.

Orientation rule

According to this rule, the orientation of the facet must be defined in two different ways.

The Vertex rule

This rule states that every triangle must share two vertices with another triangle. Also, the vertex rule is important when tessellating the 3D object’s surface.

The all positive octant rule

This indicates that the triangle vertices’ coordinates must be positive. Therefore, the 3D object must live in the all-positive octant. This helps to save space. If the 3D object stays anywhere in the coordinate space, there will be negative coordinates.

How can you optimize .STL files?

The .STL file approximates a CAD model’s surface with triangles. Also, the facets will have to introduce coarseness to the model because the approximation isn’t perfect. This same coarseness is ultimately used to print the object. The approximation can be better when the triangles become smaller. Therefore, this results in top-quality prints. The smaller the size of the triangle, the more the triangles needed to cover the surface.

Therefore, this can result in huge .STL files. This will create a problem as it isn’t easy to upload huge files. Therefore, it is important to strike a balance between the print quality and the file size. The majority of CAD software provides some settings when exporting STL file formats. With these settings, you can control the facets’ size and improve the print quality.


The .STL file is an important file format in 3D printing. Therefore, this article provided vital information about it.