Saving OBJ files as STL format is a common task for those working with 3D models. This process allows you to convert 3D models from one file format to another, making it compatible with various software and 3D printing devices. To perform this conversion, you can use software like Blender, MeshLab, or online conversion tools. One way to do this is by using Blender, which is a free and open-source 3D creation suite. Here's a step-by-step guide:

1. Open Blender and import the OBJ file by going to File > Import > Wavefront (.obj).

2. Once the OBJ file is imported, click on the 'Object' mode and select the 3D model.

3. Next, go to File > Export > Stl (.stl) to save the OBJ file as an STL file.

4. Choose the desired settings and click 'Export' to save the file in STL format.

MeshLab is another powerful tool for converting OBJ to STL. Here's how you can do it:

1. Open MeshLab and import the OBJ file by clicking on File > Import Mesh.

2. Once the OBJ file is loaded, go to File > Export Mesh As and choose 'STL' as the file format.

3. Adjust the export settings if necessary and click 'Save' to convert the OBJ file to STL.

For those who prefer online tools, there are several websites that offer OBJ to STL conversion. Simply upload the OBJ file, select the STL format, and click 'Convert' to save the file in STL format.

When saving OBJ files as STL, it's important to consider the geometry and topology of the 3D model. Some features or details may be lost in the conversion process, so it's crucial to inspect the resulting STL file to ensure it meets your requirements.

In conclusion, converting OBJ files to STL format is essential for 3D modeling and 3D printing purposes. Whether you use software like Blender or MeshLab, or opt for online conversion tools, the process is relatively straightforward. By following the steps outlined above, you can easily save OBJ files as STL files for your desired applications.