Why does it even matter? Well, a file format is the standard way that your encoded info is stored in a computer file. It indicates how bits encode information in a digital medium for storage.
What is a 3D Printer File Format?
A file extension/format/suffix is the group of characters found at the end of the file. It helps the operating system of your device (like MacOS or Windows) associate your file to a program on the computer.
That’s why you’d probably want to use the most common file formats so that they’re readable by any computer or device you might interact with.
So what the 3D file format does is that it stores information about your 3D models like plain text or binary data. But most importantly they encode the 3D model’s animations, scene, appearance, and geometry.
The 3D file formats can store one, a selection, or all the previous info.
How many 3D printing file formats are there?
Hundreds. This is because every CAD (Computer-aided design) software manufacturer has their own format that’s fine-tuned to their software.
Hence, if you use AutoCAD you get a DWG file. If you use Blender, you get a BLEND file.
This is why sharing 3D files and models to people who use different file formats (CAD software) can be a little tricky.
Neutral 3D file formats work on solving this
Neutral or open source formats work as an intermediary between formats.
STL (.STL) and COLLADA (.DAE) are two of the most commonly used neutral formats.
So, What file formats are used in 3D Printing?
STL (StereoLithography) is a very important neutral 3D file format in the 3D printing, rapid prototyping and CAD software realm.
It’s native to the stereolithography CAD software made by 3D Systems and its corresponding file extension is (.STL).
STL encodes the geometry of the 3D model using triangular mesh. It basically ignores scene, animations, and appearance.
How minimal it is makes it simple and lean. It specifies both ASCII and binary representations.
The drawback to STL is that it’s an approximate format, and recently, printing processes have reached micron level accuracy.
Moreover, 3D printers can now print in full color and STL is unable to encode color information. That’s why formats like OBJ, 3MF, or AMF might get more attention and popularity.
If you’re printing with no colors or if you want to transfer an uncolored model to another designer, the STL format should be just fine for you.
The OBJ file format is also neutral and very popular in the 3D printing field. It’s commonly used in 3D graphics and its corresponding file extension is (.OBJ).
The OBJ file format supports both approximate and precision encoding of surface geometry.
It doesn’t limit the surface mesh to triangular facets if you’re using approximate encoding. OBJ allows you to use polygons such as quadrilaterals.
On the other hand, when you’re using precise encoding, it utilizes smooth curves and surfaces such as NURBS.
Furthermore, it has the ability to encode color and texture information. However, this information is stored in a separate file with an .MTL extension (Material Template Library).
A drawback to an OBJ file is that it doesn’t support any type of animation.
It does specify both ASCII and binary encoding, but only the ASCII encoding is an open source (neutral).
Because of the fact that it’s neutral, it’s one of the more common interchange formats for 3D graphic designers. It’s also gaining popularity in the 3D printing industry as printers are moving toward full-color printing.
This extension is most commonly used in the film industry and video games. Its corresponding file extension is (.FBX).
It was developed by Kaydara but later on, bought by Autodesk. Since the acquisition, Autodesk has used it as an interchange format for its own portfolio that includes AutoCAD, Maya, 3DS Max, and Fusion 360.
The FBX file format supports appearance-related information like color and textures as well as geometry.
It also supports skeletal animations and morphs, besides supporting both binary and ASCII files.
When it comes to animation, FBX is one of the most popular choices. It can also be used as an exchange format between Mudbox, Maya, MotionBuilder, 3DS Max, or any other proprietary software.
Collada is also most commonly used in the video game and film industry. The file extension corresponding to it is (.DAE).
The COLLADA format supports appearance-related characteristics like color, material, textures, and animations, as well as geometry.
Moreover, it’s one of the select few formats that support kinematics and physics.
It stores data using the XML markup language.
When COLLADA was created, it was supposed to become a standard among 3D file formats. This did happen, and that’s why many 3D modeling software supports the COLLADA format.
However, it hasn’t put up with the consensus all of the time. It’s been used extensively as an interchange format for Autodesk Max/Maya in the film industry, but now the industry is shifting towards OBJ, FBX, and Alembic.
If you’re looking for flexible software and hardware in the 3D printing pipeline, go for STL.
Almost all software and hardware that’s commonly used in 3D printing will support STL, so you’ll have more freedom selecting your CAD programs, Slicers, and tools.
It also enables you to download plenty of ready-to-use 3D models and provides you with sufficient documentation and support.
It also works well for 3D printers that don’t have a lot of precision.
You should go for the OBJ format if you want to print multi-colored 3D models, want a lot of ready-to-use models, and have a high precision 3D printer.
Go for the FBX or COLLADA extensions if you’re going to do a lot of animated work, especially that is related to video games or the film industry.