Blender is a powerful 3D modelling software that allows you to create stunning 3D models, animations, and simulations. When you're ready to share your creations or work with them in other software, saving your files as OBJ format is a great way to ensure compatibility. Here's how you can save your Blender files as OBJ:

1. Open your Blender project and make sure you have your 3D model ready for export.

2. Navigate to the 'File' menu at the top left corner of the screen and select 'Export'.

3. Choose 'Wavefront (.obj)' from the list of available file formats.

4. A new window will appear with additional options for the OBJ export. Here you can choose the file destination, name, and various export settings such as scale and smoothing.

5. Once you've configured the export settings to your liking, click 'Export OBJ' to save your file.

By following these simple steps, you can easily save your Blender files as OBJ and ensure that they can be used in other 3D modelling software or shared with others. OBJ files are widely supported across different software, making them a great choice for sharing your 3D models with others who may not use Blender.

Keep in mind that OBJ files do not retain certain features or advanced materials that are specific to Blender. When you export as OBJ, some things like rigging, animation, and particle systems may not be preserved. For more complex files, consider other file formats or exporting multiple file types to ensure all aspects of your project are retained.

In conclusion, saving your Blender files as OBJ is a simple and effective way to ensure compatibility with other software and ease of sharing. With just a few clicks, you can export your 3D models and continue working with them in other programs. Whether you're collaborating with others or simply need to work across different software platforms, OBJ export in Blender is a valuable tool for any 3D modeller.