My study notes on use of the ZBrush SliceCurve brush…
The SliceCurve brush allows you to slice to define new polygroups by drawing a line with bezier curves.
The SliceCurve brush, once selected, is enabled as the active selection tool when you press CTRL + SHIFT.
When working with this brush, we’re creating polygroups. So, to be able to see the polygroups, it’s best to be to turn on polygroups before using the brush (SHIFT + F).
You probably also want to ensure that Perspective is turned off.
If your mesh is a 3D-Primitive, you’ll need to convert it to a PolyMesh3D by pressing the ‘Make PolyMesh3D’ button in the Tool palette.
Press the sequence B, S, I to quickly select the SliceCurve brush.
Click on the canvas or the model wherever you want the slice to begin, press CTRL + SHIFT and begin dragging. Once you start drawing the slice line, you can release CTRL+SHIFT so that your hand is free to add bezier points in the slice as you draw. The shaded side of the line shows the direction where the new ploygroup will be created on the model.
As you’re drawing, tap the ALT key to lay a bezier point, which allows you to curve the slice.
If you double-tap the ALT key, it will lay down a sharp point, which allows you to put a hard angle on the slice.
You can press and hold the SPACE bar to move the entire slice line as a whole.
This brush doesn’t use standard symmetry and can’t be used on a mesh with multiple subdivision levels. If you wish to maintain your subdivisions, first use the Freeze Subdivision Levels option located in the Tool > Geometry menu. When you’re done doing your slicing, you can then click Freeze SubDivision Levels again to turn it back off and get your subdivisions back with the new polygroups still on the model. You can establish symmetry by using Mirror and Weld in that same menu.
Press CTRL + SHIFT and click on a polygroup to isolate the polygroup, hiding all the others.
CTRL + SHIFT click on an empty area in the canvas to make all the polygroups visible again.