ZBrush Tip: Splitting Hidden Geometry into Independent SubTools

Splitting hidden geometry is a fast way to turn selected regions of a ZBrush model into independent SubTools. It is especially useful for separating clothing, armor plates, accessories, mechanical components, or any area that needs its own sculpting and transformation controls.

Use this reliable workflow:

• Create a backup first. Duplicate the SubTool or save an incremental ZPR file before changing its structure. Splitting can affect subdivision history, and the resulting boundary may require cleanup.
• Define the region to separate. If possible, assign the target polygons to a Polygroup. Clear PolyFrame mode temporarily when you need an unobstructed view, then enable it again to verify the boundary.
• Control visibility. Hold Ctrl+Shift and click a Polygroup to isolate it. Use the selection brushes when the desired region does not already have a clean Polygroup.
• Check what is visible. The command separates the hidden polygons, not the visible ones. Confirm that the portion intended for the new SubTool is hidden before proceeding.
• Run Split Hidden. Navigate to Tool > SubTool > Split > Split Hidden. ZBrush moves the invisible geometry into a new SubTool while leaving the visible portion in the original SubTool.

After splitting, inspect both SubTools from several angles. The operation follows polygon boundaries, so an imprecise visibility selection can produce stepped edges, thin polygon fragments, or unwanted islands.

• Rename immediately: use descriptive names such as “Torso,” “Chest_Plate,” or “Panel_Left” rather than leaving generic SubTool names.
• Inspect open borders: splitting a continuous surface can create exposed boundaries. Keep them open for clothing shells and panel work, or close and rebuild them when a watertight volume is required.
• Verify subdivision levels: ZBrush may display a warning when a topology-changing action conflicts with subdivision history. Do not confirm until a backup exists. If preserving high-resolution detail is essential, duplicate the source, prepare compatible topology, and project the details afterward.
• Check thickness: a separated surface may be infinitely thin. For armor, fabric, or product panels, add controlled thickness with Extract, ZModeler, panel loops, or another suitable modeling method.
• Clean the edge: use masking, Move Topological, ZModeler, or polish tools to refine the new boundary without disturbing neighboring forms.

A useful production habit is to establish clean Polygroups before hiding anything. Polygroup borders make selection repeatable and reduce accidental fragments. For irregular organic regions, zoom in closely and rotate the model while checking the hidden boundary from the front, back, and sides.

Quick distinction: Split Hidden responds to visibility, while Split Masked Points responds to masking and Groups Split separates Polygroup islands. Choose the command that matches how the model is organized.

Artists expanding their sculpting or modeling workflow can explore ZBrush solutions at NOVEDGE and visit the NOVEDGE catalog for complementary design and visualization tools.

You can find all the ZBrush products on the NOVEDGE web site at this page.