File formats for 3d printers

How To Choose the Right 3D Printing File Format

Some 3D printing file formats hold more information than others, giving your 3D printer more detailed instructions. Whether this is beneficial depends on what you are printing and your desired specifications. 

For example, STL is the most common 3D printing file format because it works for simple models but only contains external surface and shape information. If you want texture and multi-colour data, you should use OBJ.

The fundamental difference between 3D printing files is the level of information they can carry, so there is a difference in the quality and accuracy between file types. This means you can improve quality with a more detailed file type.

This article discusses the best 3D printing files and lists the leading 3D printing file formats in 2023 with examples of when you should use them.

STL

STL is the default 3D printing file. It defines 3D objects as a mesh of tessellated triangles defined by vertices coordinates, with simplicity and ease of use making it perfect for simple 3D models and multi-machine compatibility.

Every 3D printer, slicer, and CAD tool supports STL files, and you can produce relatively complex shapes. However, it does not support colours, materials, textures, or scale, so you are limited by triangular definitions.

OBJ

OBJ is a step up from STL because it uses multiple polygons (including hexagons and triangles) to define 3D models. This lets you create smoother, more accurate models that print with higher quality than STL.

OBJ contains colour and texture information, and it is supported by almost every slicer, CAD tool, and 3D printer. However, it contains no scale information, which can create sizing problems with repeated production.

3MF

3MF is the potential new standard for 3D printing files. It introduces scale units, colours, mesh, material, and texture data – ideal for producing detailed models. 3MF can manage multiple geometries and use them independently.

Fusion 360 supports 3MF, letting you convert every detail into a 3D printing file. Uniquely, the 3MF file format is “human-readable,” meaning you can understand the file and edit it. No other 3D printing file is so capable.

VRML

VRML is an alternative file type to STL for printing models in multiple colours. VRML files can hold a single UV colour map, so they are ideal for 3D printers with two extruders and models with more than one colour.

You still get a low-resolution 3D model, so the level of detail is lower than 3MF or OBJ, but you get more colours than STL. The most significant limitation is VRML does not support transparent or rubber-like materials.

Which 3D printing file format is best?

3MF is the best 3D printing file format as far as outright information is concerned, but that does not make it the best file format for your model.

STL files
Credit

STL is the most popular file format because it is simple, lightweight, widely supported, and sufficient for most 3D printing applications. You don’t need anything more than STL unless you need texture, colour, and material data.

OBJ is a step up from STL with multiple polygons rather than only tessellated triangles, capturing more detail and increasing accuracy. This makes OBJ a superior file format, albeit with a larger and more complex file.

The quality difference between file formats

As we discussed earlier, the fundamental difference between 3D printing files is the level of information they can carry. This ultimately affects the quality of prints, although quality requirements are entirely subjective.

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STL files produce the most basic models because they use only tessellated triangles to define shapes. OBJ files capture more detail with additional polygons – you can think of this as an OBJ file “smoothing” the model.

3MF files produce the most accurate, true-to-design models because they include significantly more information. 3MF is an XML-based data format designed specifically for additive manufacturing, containing material, colour, texture, and scale information, giving your 3D printer instructions that cover every angle.

Recognising when you need more model data

STL files are perfect for producing simple models with minimal detail. However, you might need more data to produce true-to-design models.

Because STL files only store the external surface and shape of 3D models, they are unsuitable for complex shapes. For complex objects, you should choose a 3D printing file that captures more detail, such as OBJ or 3MF.

However, just because a specific file format captures more information about your model does not mean it is better for your intended application.

Ask yourself: what type of data do you need your 3D printer to have? If it is anything more than surface data, skip STL and look at OBJ and 3MF.

Summing up

Choosing the correct 3D printing file format comes down to a simple question: what data does your 3D printer need to produce a true-to-design model?

If it only needs surface information and tessellated triangles capture the form and essence of your model, STL is an ideal file format. If you also need colour and texture information, an OBJ file will give you the necessary data.

If you need scale, material data, and complex geometries, 3MF is the best file format, although it is less well-supported.

If you enjoyed this article covering how to choose the right 3D printing file format, read our piece on how to choose a 3D printing material.

Find out more

For help with 3D printing or to find out more about the 3D printing files listed in this article, please get in touch with the team at 01765 694 007, email team@additive-x.com, or you can

 

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