Fusion 360 is a powerful 3D modeling software, and exporting OBJ files with materials can be a useful feature for working with 3D models in other applications. Here's how to do it:

1. Prepare your 3D model with materials in Fusion 360. Make sure to apply textures and materials to the different parts of the model to enhance its appearance.

2. Once your model is ready, go to the 'File' menu and select 'Export'. Choose 'Export to OBJ' from the options.

3. In the Export to OBJ dialog, make sure to check the 'Include Material and Texture Files' option. This will ensure that the materials and textures used in your model are included in the export.

4. Choose a location to save your OBJ file and click 'OK' to export it.

5. Fusion 360 will create an OBJ file along with a separate MTL file that contains the material and texture information. These files can be used in other 3D applications to ensure that the materials from your Fusion 360 model are preserved.

6. You can now import the OBJ file into other 3D modeling and rendering software, such as Blender or 3ds Max, and the materials should be applied correctly.

By following these steps, you can export 3D models with materials from Fusion 360 to OBJ format for use in other applications. This can be helpful for creating realistic visualizations, conducting 3D printing, or integrating your models into game development projects. Now you can make the most of your Fusion 360 models by preserving their materials when exporting to OBJ.