Are you working with 3D design files in STP format and need a reliable way to view them for free? Whether you're a professional engineer or a hobbyist, having the right STP file viewer can make a world of difference. Fortunately, there are several free options available for both Windows and Mac. Here are 5 free STP file viewers that you can use to open and view your 3D models:

1. FreeCAD: FreeCAD is an open-source parametric 3D modeler that also functions as a versatile STP file viewer. It supports a wide range of file formats and offers powerful features for creating and manipulating 3D models.

2. eDrawings Viewer: eDrawings is a free STP file viewer designed for both Windows and Mac. It allows you to view, print, and review STP and other 3D model files with ease. The viewer also supports various annotation and measurement tools.

3. Autodesk Viewer: Autodesk Viewer is a web-based tool that allows you to view and share 2D and 3D design files, including STP files. You can access the viewer from any web browser and easily collaborate on your 3D designs.

4. SolidWorks eDrawings: SolidWorks eDrawings is a free STP file viewer that enables you to view, print, and review 3D models in STP and other formats. It offers cross-platform compatibility and supports advanced visualization and markup capabilities.

5. A360 Viewer: A360 Viewer is a cloud-based viewer that enables you to open and view 2D and 3D design files, including STP files. You can access the viewer from any device with an internet connection and seamlessly collaborate on your design projects.

With these free STP file viewers, you can easily open, view, and share your 3D models without spending a dime. Whether you're a professional designer, engineer, or simply someone who wants to explore 3D models, these tools offer a convenient and cost-effective solution. Try out one of these free STP file viewers and take your 3D design projects to the next level!