How to mask an entire faceset during sculpting

Question

I am working on multiple objects all required to preserve some details, which can be done using masking in sculpting.

Can any one help me with a script which can mask first/single faceset on one click.

Or any other way where I dont have to hide/show the faceset again and again.

Answer 1

You can mask a face set by pressing Shift+A to create a mask that starts on the face set, and then hold Ctrl to make it fill one (or more) face sets.

Answer 2

Here is an add-on script that creates a mask from the face set under the mouse pointer on a single key press. Shortcut key is Y. The menu entry is located under View3D > Mask > Mask From Face Set in Sculpt mode.

The operator is only four lines but for the shortcut key, a few more lines are required.

bl_info = {
    "name": "Mask From Face Set",
    "description": "Creates a mask from the face set under the mouse.",
    "author": "Blunder",
    "version": (1, 0),
    "blender": (2, 80, 0),
    "location": "View3D > Mask > Mask From Face Set",
    "support": "COMMUNITY",
    "category": "Sculpt",
}

import bpy

class MaskFromFaceSetOperator(bpy.types.Operator):
    bl_idname = "wm.mask_from_face_set"
    bl_label = "Mask From Face Set Operator"

    def execute(self, context):
        bpy.ops.paint.mask_flood_fill(mode='VALUE', value=0)
        bpy.ops.sculpt.face_set_change_visibility(mode='TOGGLE')
        bpy.ops.paint.mask_flood_fill(mode='INVERT')
        bpy.ops.sculpt.face_set_change_visibility(mode='SHOW_ALL')
        return {'FINISHED'}

# Only needed if you want to add into a dynamic menu.
def menu_func(self, context):
    self.layout.operator(MaskFromFaceSetOperator.bl_idname, text="Mask From Face Set")

# store keymaps here to access after registration
addon_keymaps = []

# Register and add to the mask menu (required to also use F3 search "Mask From Face Set Operator" for quick access).
def register():
    bpy.utils.register_class(MaskFromFaceSetOperator)
    bpy.types.VIEW3D_MT_mask.append(menu_func)
    
    # handle the keymap
    wm = bpy.context.window_manager
    # Note that in background mode (no GUI available), keyconfigs are not available either,
    # so we have to check this to avoid nasty errors in background case.
    kc = wm.keyconfigs.addon
    if kc:
        km = wm.keyconfigs.addon.keymaps.new(name='Sculpt', space_type='EMPTY')
        kmi = km.keymap_items.new(MaskFromFaceSetOperator.bl_idname, 'Y', 'PRESS', ctrl=False, shift=False)
        addon_keymaps.append((km, kmi))

def unregister():
    # handle the keymap
    for km, kmi in addon_keymaps:
        km.keymap_items.remove(kmi)
    addon_keymaps.clear()
    
    bpy.utils.unregister_class(MaskFromFaceSetOperator)
    bpy.types.VIEW3D_MT_mask.remove(menu_func)

if __name__ == "__main__":
    register()