Adding more spheres to an obj in Zbrush can greatly enhance your 3D modeling and sculpting capabilities. Here's a quick guide on how to do it.

1. Open your Zbrush project and select the subtool that you want to add more spheres to.

2. Go to the Tool palette and select the Sphere3D tool. This will create a new sphere that you can use to add to your obj.

3. Position the new sphere where you want it to be in relation to your existing subtool. You can use the Move, Scale, and Rotate tools to adjust the position and size of the sphere as needed.

4. Once you're happy with the placement of the new sphere, you can merge it with the existing subtool. To do this, go to the Subtool palette and click on the Merge Down button. This will combine the new sphere with the existing subtool, allowing you to sculpt and manipulate them together.

5. You can repeat this process to add as many spheres as you need to your obj. Each new sphere can be positioned and merged with the existing subtool to create complex 3D shapes and forms.

By adding more spheres to your obj in Zbrush, you can unlock new creative possibilities for your 3D modeling and sculpting projects. Experiment with different shapes, sizes, and arrangements to see what interesting designs you can come up with. Happy sculpting!