You can subtract masks in ZBrush using a combination of masking and visibility controls, particularly when dealing with polygroups.
Understanding Mask Subtraction in ZBrush
ZBrush's masking tools are powerful for isolating and manipulating specific areas of your model. Subtracting from a mask allows you to refine it and target more complex regions. Here's how you can do it, especially when polygroups are involved:
Method for Subtracting Masks Using Polygroups
Here's the process, based on the provided reference:
-
Initial Mask: Begin by creating your initial mask on the mesh.
-
Isolate the Polygroup: If you wish to subtract a specific polygroup from your existing mask, Shift-Click on the polygroup. This action will hide all of your model except for the selected polygroup.
-
Clear the Mask from the Polygroup: With only the polygroup visible, Ctrl-click on an empty space in the canvas. This action will clear the mask from that specific polygroup.
-
Restore Visibility: Shift-Ctrl click on an empty space in the canvas. This will restore the visibility of all other parts of your mesh.
- The result is that the area covered by the polygroup will now be removed from your original mask.
Key Commands
Here's a summary of the commands:
| Command | Action |
|---|---|
| Shift-Click on a Polygroup | Hides everything except for the selected polygroup |
| Ctrl-Click on empty canvas | Clears the mask on all visible mesh areas |
| Shift-Ctrl-Click on empty canvas | Restores the visibility of hidden mesh areas |
Practical Example
Let’s say you have a mask that covers a large portion of a character's face and you have a specific polygroup defined for their ear that you do not want masked. Follow the method above:
- Draw the mask across the face including the ear area.
- Shift-click on the ear polygroup. Only the ear is now visible.
- Ctrl-click on the canvas. The ear is no longer masked.
- Shift-Ctrl click on the canvas, the rest of your mesh returns to view. The ear is not masked, effectively subtracting it from the initial face mask.
Alternative Methods
While the polygroup method is efficient, here are some other ways to manipulate masks, though not direct subtractions:
- Ctrl-Drag Mask: You can use the Ctrl key while dragging on the mesh to unmask areas. This can be helpful if you just need to remove portions of the mask on any polygroup.
- Using Masking Brushes: You can use brushes with Ctrl enabled to erase parts of an existing mask.
- Masking Selections: Ctrl-Click on a Masked area will invert the mask, and you can Ctrl-Drag on the unmasked area to turn it into a masked area.
Summary
By using combinations of these controls, you can quickly and precisely subtract from a mask in ZBrush, allowing you to refine your selections with great flexibility.
