ZBrush is a powerful tool for 3D modeling, and exporting an OBJ file from ZBrush is a common task for 3D artists. Here's a step-by-step guide on how to do it:

1. Once you have completed your 3D model in ZBrush, make sure it is in the highest subdivision level and all the details are sculpted.

2. Go to the 'Tool' palette and select the subtool you want to export as an OBJ. If you have multiple subtools, you can merge them into a single subtool by selecting 'Merge' from the 'Subtool' palette.

3. With the desired subtool selected, go to the 'Tool' palette and click on 'Export'. Choose the location where you want to save the OBJ file and give it a name.

4. In the export options, make sure to select 'OBJ' as the file type and choose any additional settings you may require, such as exporting vertex colors or texture maps.

5. Click 'Export' to save the OBJ file to your chosen location.

By following these steps, you can easily export an OBJ file from ZBrush for use in 3D modeling software such as Blender, Maya, or 3ds Max. OBJ files are a popular and widely supported file format for 3D models, making them a great choice for sharing or collaborating on 3D projects.

Remember to always check the scale and orientation of your exported OBJ file to ensure it imports correctly into other 3D software. Additionally, if you have multiple subtools or parts of your model, you may need to export each subtool as a separate OBJ file.

Exporting an OBJ file from ZBrush is a straightforward process that allows you to take your 3D models into other software for further refinement, rendering, or animation. Whether you are a beginner or an experienced 3D artist, mastering the export process in ZBrush is essential for seamless integration into your 3D workflow.