When working with Adobe Illustrator, you may want to convert your 2D designs into 3D models for further manipulation. One way to do this is by saving your Illustrator file as an OBJ format, which is commonly used for 3D modeling purposes. Here's how to save your Illustrator file as an OBJ:

1. Open your Illustrator file and ensure that your design is ready for export. This may include creating separate layers for different elements of your design, as this will make the conversion process smoother.

2. Once your design is ready, go to 'File' and select 'Save As'. In the 'Save As' dialog box, choose a location to save your file and select 'Wavefront Object (*obj)' from the 'Save as type' dropdown menu.

3. Click 'Save' to export your file as an OBJ. A new dialog box will appear, allowing you to adjust the export settings. Here you can specify the scale, units, and other options for the OBJ file. Make any necessary adjustments and click 'OK' to complete the export process.

4. Your Illustrator file has now been saved as an OBJ format, allowing you to import it into 3D modeling software for further editing and manipulation. You can use the OBJ file to create 3D renderings, animations, or even 3D printing.

By following these simple steps, you can easily convert your Illustrator file into an OBJ format, opening up a world of possibilities for 3D modeling and design. Whether you're a graphic designer, architect, or hobbyist, knowing how to save your Illustrator files as OBJ formats can greatly expand your creative potential.