ZBrush is a popular digital sculpting and painting software that is widely used in the 3D industry. It allows artists to create high-resolution 3D models for various purposes such as video games, movies, and animations. If you want to work with existing 3D models, you might need to import OBJ files into ZBrush. Here's how you can do it.

1. Launch ZBrush and open the Tool palette.

2. Click on the 'Import' button in the Tool palette to bring up the file browser window.

3. Navigate to the location where your OBJ file is saved and select it.

4. Click 'Open' to import the OBJ file into ZBrush.

Once the OBJ file is imported, you will be able to see the 3D model in the ZBrush workspace. You can then start sculpting, painting, and adding details to the model using the various brushes and tools available in ZBrush.

It's important to note that ZBrush supports OBJ files with a specific file structure and polygon format. If your OBJ file doesn't import properly, it could be due to issues with the file itself. Make sure that the OBJ file is in the correct format and doesn't have any errors.

In addition to importing OBJ files, ZBrush also allows you to export your sculpted models as OBJ files. This can be done by selecting the Subtool you want to export, clicking on the 'Export' button in the Tool palette, and saving the file in OBJ format.

By being able to import and export OBJ files in ZBrush, you can seamlessly work with 3D models from other software and collaborate with other artists. Whether you're a beginner or an advanced 3D artist, ZBrush provides powerful tools and capabilities to bring your creative visions to life.

In conclusion, opening OBJ files in ZBrush is a straightforward process that allows you to work with existing 3D models and unleash your creativity. By following the steps outlined above, you can import OBJ files into ZBrush and start sculpting and painting to bring your 3D creations to the next level.