If you're into 3D printing or CAD design, you know how important it is to have a reliable STL viewer for Mac OS X. Whether you're looking to view 3D models, make edits, or prepare files for printing, having the right software can make all the difference. Here are some of the top options for STL viewers on Mac OS X:

1. MeshLab: MeshLab is a powerful open-source tool for processing and editing 3D triangular meshes. It supports a wide range of file formats, including STL, and offers a variety of tools for viewing and analyzing 3D models.

2. FreeCAD: FreeCAD is a free and open-source parametric 3D CAD modeler. In addition to creating 3D models, FreeCAD also provides robust support for viewing and editing STL files on Mac OS X.

3. SketchUp: SketchUp is a popular 3D modeling software that offers a user-friendly interface and powerful tools for creating and editing 3D models. While it's primarily known for its modeling capabilities, SketchUp also supports the import and export of STL files, making it a great option for viewing and editing STL files on Mac OS X.

4. Blender: Blender is a comprehensive open-source 3D creation suite that supports the entire 3D pipeline, including modeling, rigging, animation, simulation, rendering, compositing, and motion tracking. It also provides support for viewing and editing STL files, making it a versatile option for Mac OS X users.

5. AutoCAD: AutoCAD is a leading CAD software used by professionals for 2D drafting and 3D design. It offers robust support for viewing and editing STL files on Mac OS X, making it a great option for those with more advanced design needs.

Whether you're a hobbyist looking to view 3D models from the web, or a professional designer working with complex CAD files, having a reliable STL viewer for Mac OS X is essential. Consider trying out one of the options listed above to find the best fit for your needs. With the right software, you can streamline your 3D printing and design workflow and bring your ideas to life with ease.