How to Separate Meshes in ZBrush?

You can separate meshes in ZBrush primarily by masking the areas you want to split, assigning them to a unique PolyGroup, and then using the Group Split function in the Subtool menu. This method allows you to divide a single mesh into multiple distinct subtools based on their PolyGroup assignments.

Steps for Separating Meshes Using Masking and PolyGroups

Separating parts of your mesh into individual Subtools is a fundamental process for managing complex models in ZBrush. The most common and flexible way involves leveraging PolyGroups. Here's how it works:

1. Mask the Polygons: Begin by masking the specific area or polygons you wish to separate from the rest of your mesh. You can do this using ZBrush's various masking brushes (e.g., Mask Pen, Mask Lasso) while holding down the Ctrl key.
2. Create a Separate PolyGroup: Once the desired area is masked, press Ctrl + W. This action will automatically assign all the currently masked polygons to a new, unique PolyGroup. The unmasked polygons will retain their original PolyGroup(s).
3. Split the Mesh by PolyGroups: Navigate to the Subtool palette. Open the Split sub-menu and select Group Split. This function analyzes your mesh and separates it into multiple distinct Subtools, with each new Subtool corresponding to a unique PolyGroup on the original mesh.

As noted in the reference, after using Subtool > Split > Group Split, you should now have multiple separate meshes listed in your Subtool palette. For instance, if you masked and PolyGrouped the jaw area of a head model, applying Group Split would result in two separate meshes: one for the main part of the head (minus the jaw) and one specifically for the jaw.

This technique is incredibly versatile, allowing for detailed control over which parts of your model become separate objects, making organization and further sculpting or processing much easier.