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Making Sense of 3D Printer File Types


There are numerous 3D printer file types to choose that allow you to take advantage of 3D printing technology. But it can be hard to understand which file type you should be using and which is best for your needs?

This is a question you most likely are asking yourself at the moment, and many other people also find themselves in this situation.  

In this article, I will take you through an in-depth guide on the different file types. Furthermore, you will also learn about the pros and cons of every format. Therefore, without wasting much time, let us take you through some of the most popular file types such as AMF, OBJ, 3MF, and STL. 

With this in mind, you will be able to make an informed choice regarding which 3D printer file type best suits your needs. 

STL 3D Printer File Type

This is, without a doubt, the most common 3D printer file type used by most of the 3D printing community. The invention of this file format dates back to when Chuck Hull discovered 3D printing technology. 

It then went ahead to remain as the preferred format for the last 30 years despite its restrictions and age. This is because this file type ensures you get reliable support on any hardware and software piece when designing 3D printed objects. 

One of the reasons this file format is loved by many is due to its simple nature. The features integrated into it that make it stand out include:

  • It supports both binary encodings (smaller sized files) as well as ASCII (human-readable, bigger file sizes).
  • It makes use of the very simple tessellations approach when storing geometry. Tessellations refer to the process of covering a surface either with one or several geometric shapes while making sure there are no gaps or overlaps. An excellent practical example of this is a tiled floor. 
  • Whereas this file format can encode the geometry of a 3D model, it does not support the storage of other exciting object properties. This includes details on textures, colors, and materials. 
  • The STL file type uses triangular tiles when covering a 3D model’s surface. Therefore, the normal, as well as vertices of these triangles, are stored inside a file to encode a model’s geometry. 

However, the STL file format is often criticized for being outdated, as it has only been updated once from its invention. This makes STL files relatively large in size as they carry a lot of information that is not required. In most cases, this isn’t a problem as the files are generally in the order of a few Megabytes in size.

G-Code 3D Printer File Type

G-code is the language that the majority of 3D printers understand. When you use a slicer program, it transforms a file such as an STL into G-code so that your 3D printer can understand it.

G-code can be thought of as a series of instructions and co-ordinates that tell your 3D printer where to position the print head and when to extrude filament. As well as a more detailed setting such as nozzle temperatures and bed temperatures.

This file format is also referred to as .gco or .g and is a file extension for files that contain the G-code data. The creation of the .gcode file is done using a slicing program that turns the CAD drawing to a string code, which is understandable to a 3D printer. 

If you often use 3D printing technology, then you will, without a doubt, encounter this post-slicing type of file numerous times. 

OBJ 3D Printer File Type

If you want a 3D printer file type that provides you with multicolor printing, then OBJ format is a perfect choice. The use of this format file was initially started by 3D graphic designers to act as a neutral interchange type for the 3D graphics. This then leads to the broader adoption by the bigger 3D printing fraternity after the 3D printers gained the ability to print on various materials and colors. 

Whereas other 3D graphics formats such as COLLADA and FBX could also do the same task, the OBJ file type is often preferred. This was due to the file format’s simplicity as well as an open-source license. 

Therefore, CAD manufacturers had a much simpler task writing consistent parsers when importing and exporting files in comparison to its alternatives COLLADA or FBX. This is what made OBJ file format preferred as the ideal choice for multicolor printing. 

Some of the features to expect from this file format include:

  • Flexibility in the manner in which geometry is encoded. This means you can make use of tessellations that have polygons when covering the surface of objects, thereby ensuring the file’s precision and size are of perfect balance. 
  • It incorporates open-source information, so it supports both binary and ASCII encodings.
  • The OBJ file format allows you to encode a 3D model’s geometry together with details about textures, materials as well as color. 
  • This file format incorporates the MTL (Materials Template Library) file extension format, which allows you to store texture and color information. The combination of the MTL file and the OBJ files enables you to make a multi-colored texture object. Additionally, the MTL file format defines properties such as diffuse color, ambient color, transparency, specular color, and many more. 

AMF 3D Printer File Type

It is an updated version of the STL file type hence why it is often labeled “STL 2.0”. This version was launched in 2011 and was developed to address some drawbacks of the STL file format. These file type fixes issues such as being error-prone, slow, bloated, as well as the inability to store texture, material, and color information. 

Because of these problems, there was a need to develop a modern 3D printer file type native to additive manufacturing, and consequently, AMF 3D printer file format was born. This file type is an XML based format that incorporates in-built support for orientation, color, scale, geometry, materials, duplicates, and lattices. 

With all these technical advancements, this file format is undoubtedly a better version of the STL file format. Nevertheless, its adoption by the 3D printing community has been quite slow. 

The features to expect from this file format include:

  • It uses am XML format, which is human-readable to solve the STL drawbacks by incorporating a hierarchy of five elements, that is, metadata, constellation, material, object, and texture.
  • It includes wide-ranging metadata fields such as name, company, author, tolerances, volume, description, among many others. 
  • This file format lets the 3D printer select the required information for its operation irrespective of whether it is new or old. For instance, if your 3D printer can only operate with a single material, then every other multi-material details are overlooked. This same principle applies to every other element, including composition, texture, and color. 
  • The AMF file format uses triangular meshes to describe object surfaces similar to STL. However, one distinguishing element is that it includes both planar straight triangles and curved triangles. The use of curved triangles allows you to describe curved surfaces without needing to use lots of facets. 
  • This 3D printer file type is simple to read, write as well as the process. 
  • It also incorporates the “constellation” feature that lets manufacturers specify an object’s relative pattern. This crucially helps in the arrangement of numerous objects while stating the orientation and location. 

Whereas the AMF file format incorporates some distinct innovations, it also has several shortcomings. This includes lacking some essential features and some of its features not being well elaborated. 

VRML 3D Printer File Type

VRML stands for Virtual Reality Modelling Language and is a newer 3D file format compared to STL. This 3D printer file type can hold one UV color map, thereby making it an excellent choice for 3D printers, which incorporate two extruders as well as for models that have over one color. 

Nevertheless, the use of this file format is not widespread, but it still receives applause because it has color data. 

3MF 3D Printer File Type

This 3D printer file type was developed by Microsoft and was aimed to address the issue that AMF failed, and that is adoption.

The developers of AMF, ASTM, did a miscalculation by developing this innovative technology without including big players in the 3D printing industry. Consequently, this resulted in the slow adoption of the AMF file format. 

Microsoft learned from that mistake, took a different route during the development of the 3MF file format. They started by first developing this 3D printer file format internally in 2011, looking to design a high-quality and seamless 3D printing experience for the 3D printing community. 

However, they later changed their strategy and, in 2015, formed a body known as the 3MF Consortium, which included every significant player in the 3D printing industry. This comprised of Ultimaker, Shapeways, Dassault Systems, Autodesk, 3D Systems, Stratasys, Materialize, GE, HP, Siemens, and many others. 

With every big player on board, the 3MF printer file format got the essential backing of the industry’s big names. This then gives this file format an edge as both the adoption and technical issues have been explained. Therefore, it is no surprise this 3D printer file format is receiving lots of hype and publicity. 

Should the 3MF 3D printer file type be adopted faster compared to AMF, which is highly likely, then it is on its way to replace STL as the preferred 3D printer file format. 

The features integrated into the 3MF file format include:

  • Geometry illustrations identical to the triangular meshes of STL but with a size-friendly format as well as more compact in comparison to AMF. 
  • It is an XML-based format since the 3MF Consortium prioritized human readability for simplicity of development over the performance of a binary format. 
  • The files are 100% manifold without any overlapping triangles or cracks, avoiding issues in formats that have been standardized for VR and animation instead of 3D printing. Thanks to this, you can now have a ready-to-go 3D printed file that needs no fixing.
  • The 3MF file format can encode an object’s details, including textures, material, and color. 
  • It aims to simplify 3D printing to be easy and straightforward, like printing a document. Thus, all that needs to be done is choosing a printer, selecting the options, and then pressing print. 
  • It unveils the concept of “3D payload” or “single archive” This file defines every optional, standard, and compulsory parts with the detailed with full model details included in every single archive. Usually, this payload comprises digital signatures, core document properties, a 3D model, thumbnail images of every model, 3D print settings referred to as “PrintTicket,” as well as 3D texture information. 

The adoption of the 3MF file format is still not yet widespread since its development is still in its initial stages. However, this will soon change once the companies that form the 3M Consortium start using it. 

X3G 3D Printer File Type

This 3D file type is used by Makerbot and is an advanced binary file compared to the G-code file type because it comprises of the 3D printer motions and print settings. This means it contains every detail about the speed at which the 3D printer should move as well as when it should move and when it should feed and heat material. Additionally, it has codes that can be read and interpreted by the Makerbot 3D printer such as filament material types.

This replaces the earlier MakerBot file types of .MAKERBOT and .S3G

FBX 3D Printer File Type

The proprietary rights of this 3D printer file type belong to Autodesk and are made use during the exchange of data between Autodesk packages. Therefore, its primary role is to ensure the interoperability of different content creation programs, for example, Maya and Autodesk. 

This 3D printer file format is often used in game development as well as film production because it enables workflow improvements. 


After reading through this article, you now know of the different 3D printer file types. Moreover, you now understand that every file format comes with its strengths, weaknesses as well as different compatibility levels when being used with 3D printing hardware and software.

Often you will be forced to use whichever file type your hardware or software is compatible with. But if you have a choice, at least now you will be more informed to make a decision!

With this in mind, you are now better-placed to select a file format that best meets your needs. Therefore, you can continue exploring your 3D printing passion. 

Happy printing!

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