With this tool, you can flip/invert normals of all SubD surfaces.
Access and Use
You can find Normals Flipper when in Export mode:
1. Select the Blue button on your non-drawing hand
2. Go to Save & Export
3. Select the Export button
4. Press and hold the black button on your drawing hand controller, then hover over to the right to select the Normals Flipper tool
5. Intersect its tip with a SubD surface and pull the index trigger on your drawing hand to flip the normal