Have you bought a STEP file from us, or would you like to know how to open one before you buy? Here you will find free programs for your computer and your phone.
What is a STEP file?
STEP is a neutral format for 3D CAD models. The files end in .step or .stp. Many common CAD programs can open them. However, most computers and phones do not come with a suitable program preinstalled, so double-clicking the file is often not enough.
Free programs
The information comes from the developers’ websites. The links take you to their official websites and open in a new tab.
Online 3D Viewer
Right in your browser, with nothing to install. Also on phones and tablets.
- Website: 3dviewer.net
- Devices: browser on a computer, phone or tablet
- Features: view, rotate, zoom, measure (distances and angles, without units)
- Terms: free for everyone, open source; the website shows ads
- Account needed: no
- Language: English
According to the provider, your file stays in your browser and is not uploaded. One exception: the “3D print” button sends your model to an outside printing service after asking you to confirm. The website asks for cookies for advertising. Under “Manage options”, the “Legitimate interest” switches are already on. If you do not want to allow anything, switch them off and then confirm with “Confirm choices”.
eDrawings Viewer
A viewer from Dassault Systèmes, the maker of SOLIDWORKS.
- Download: edrawingsviewer.com
- Devices: Windows 11 (64-bit) and Mac; according to the developer, 16 GB of RAM or more
- Features: view, show sections
- Terms: free; on Windows, you accept the developer’s terms before downloading
- Account needed: no (on a Mac, you need an Apple account for the App Store)
- Language: English; on Windows, other languages too
On the page, choose “Win Users” or “Mac Users”. On Windows, this takes you to the SOLIDWORKS download list. There, pick “eDrawings (64-bit)”. The apps for Android and iPhone are paid.
FreeCAD
A full CAD program, free and open source. A little more complex for beginners.
- Download: freecad.org
- Devices: Windows, Mac and Linux (64-bit)
- Features: view, measure (distances, angles, lengths, areas), show sections
- Terms: free for everyone, including companies; open source
- Account needed: no
- Language: English and many others
Mayo
A small open-source viewer.
- Download: github.com/fougue/mayo
- Devices: Windows and Linux (there is no ready-made package for Mac)
- Features: view, measure (lengths, angles, areas), show sections
- Terms: free for everyone, open source
- Account needed: no
- Language: English and French
The link takes you to the project page on GitHub. The download files are listed there under “Assets”; for Windows, for example, the file with “win64-installer” in its name.
How to open your file
- After your purchase, download the STEP file and save it on your device. If it is packed, for example as a ZIP file, unpack it first.
- Install one of the programs or open the Online 3D Viewer in your browser.
- Open the file in the program, usually via “File” and “Open”. In the Online 3D Viewer, drag the file into the browser window or use the open button.
- Rotate and zoom the model with your mouse or your fingers. To measure, use the program’s measuring tool. The unit of your file is stated in the product description.
Large assemblies need a lot of memory. In the browser and on a phone, loading can then take a long time. In that case, it is better to use a program on your computer.
Programs sometimes display the same file differently. We cannot promise that a particular program will display your file completely (Terms and Conditions, § 12). If something looks wrong, try a second program or write to us.
Your file stays with you
Only load the file into programs or services where it stays private. You may not make it public or accessible to third parties, for example in forums, public cloud folders or public CAD libraries (Terms and Conditions, § 9). Some free online services upload files to their servers or make them visible to others. That is why such services are not on this list.
What you may use the file for is set out in our Terms and Conditions (§§ 6 to 11).
Check dimensions and safety yourself
A program shows you the model, but it does not check it. Before you build, check all dimensions, materials and connections yourself. For load-bearing or safety-relevant parts, have a qualified person check them (Terms and Conditions, § 13).
Questions?
Email us at info@stepmasters.de or use the contact form. We usually reply within 5 working days.
You can find all CAD models and build plans in our project overview.
About the links
The links lead to websites of other providers. We have no influence over their content. We do not receive any money for the links. The terms of the respective developers apply. All trademarks mentioned belong to their owners. Information as of 30 October 2026.