The Complete STEP to STL Conversion Guide

General Information

This guide is part of the RapidPipeline 3D Formats Knowledge Database. It shows how to convert STEP to STL, if you'd like to know more about the formats, please check out the following links:

• Learn more about the STEP format
• Learn more about the STL format
• Limitations of a STEP Files to STL Conversion Workflow

What are STEP and STL files commonly used for?

STEP

is a file format mostly used for exchange of CAD data.

STL

is a file format mostly used for 3D printing.

Limitations of a STEP Files to STL Conversion Workflow

The following limitations should be taken into account when converting STEP files to STL format:

STEP Feature (not supported by STL)	Limitation Details
Free-Form Surfaces	Free-Form Surfaces: supported in STEP, but not in STL. Free-form surfaces allow a CAD user to design surfaces with advanced controls over curvature and continuitiy. While these surfaces are common for CAD models (in the form of so-called boundary representations or "B-reps"), they need to be converted to polygonal triangle or quad data to work with most 3D rendering engines - a process called tessellation. In this example, a surface patch is used to describe a part of a curved surface of a product. Without support for this feature, the free-form surface has to be tessellated into quads or triangles.
Quad Meshes	Quad Meshes: supported in STEP, but not in STL. Quad meshes are a common way to hand-model and edit 3D models. 3D artists get intuitive control and such meshes are also easy to refine, as well as well-suited for creation of skinned animations. However, real-time rendering pipelines and hardware are usually all based on triangles, so if a 3D model should not be edited any more, it is safe to convert quads to triangles (and engines will do this automatically before sending data to the rendering hardware). In this example, a part of a mesh is modeled with quads. Without support for this feature, quads will have to be triangulated, producing a pure triangle mesh.
Materials	Materials: supported in STEP, but not in STL. Materials are a fundamental concept in 3D modeling, enabling colored and - in many cases - photorealistic rendering of the 3D model that they are applied to. There are also some formats that don't make use of 3D materials, for example because they need to solely describe a shape (e.g., for many cases in additive manufacturing). In this example, photorealistic PBR materials are used to equip the 3D model with a realistic look. Without support for materials, the model will have to be rendered with a default material (often a default shade of gray).
Scene Nodes	Scene Nodes: supported in STEP, but not in STL. Scene nodes make it possible to address parts of a 3D model separately. For example, a part could be dynamically hidden or shown as part of a 3D configurator. Without support for this feature, a 3D scene will only consist of a flat model, without parts being individually configurable.
Hierarchical Scene Graph	Hierarchical Scene Graph: supported in STEP, but not in STL. Scene graphs are one of the most common concepts in 3D computer graphics. By structuring the scene in a hierarchical way, logical parts of it can be easily addressed and transformed. This is useful in many applications, like games or 3D configurators. Without support for this feature, a 3D scene cannot be structured hierarchically, for example objects cannot be logically composed of smaller objects.

Converting and Optimizing STEP Files to STL

There are various ways to convert between STEP and STL. With RapidPipeline, you can easily convert and and optimize STEP files, at scale.
It supports STL, as well as many other file formats (examples: 3dsMax, FBX, glTF, OBJ, PLY, USD, USDZ, VRM), at high quality.

Due to the aforementioned potential limitations of STL, in principle, one cannot always perfectly convert 3D data between STL and other formats. In the following, you can find conversion guides between STL and the most important other formats, along with a rough score for compatibility of this workflow:

What's the best way to get STEP files into my 3D applications, and are there alternatives to using STL?

Doing 3D conversion right, especially at scale, can be tricky, as 3D data is in general a rather complex (yet very powerful!) medium. This also applies to STEP and STL files - the conversion guide above provides a rough first idea about that. Once you know what you would like to do, tools like RapidPipeline can help you perform the necessary steps, and to even automate the process for thousands or even millions of files.

Especially when introducing pipelines and workflows at scale in an enterprise context, it is usually good to rely on dedicated tools and expertise, making sure you do not introduce any steps into your 3D workflow that are detrimental to the final output's quality, or that take your team too much time (and money).

If you're interested to hire dedicated expertise from the best in the field to help your company reach your goals fast and reliably, please do not hestitate to contact DGG. Being the creators of RapidPipeline, and ambassadors for open 3D standards for more than a decade, we have been building some of the world's most advanced 3D pipelines, having processed many millions of 3D assets. Therefore, our expertise will help you to reach your goals faster, at scale, and with the least possible friction, since we are focused on maximum interoperability. Try out RapidPipeline for free today, or get in touch with our team here:

Sign up for a free account

to get started with 3D data conversion and optimization today!

If you have any questions, feel free to chat with our human team.