Hi Kent, sorry for the long question, but when I extract a mask initial off of the main part of the helmet, the extracted ...

The grease pencil works correctly every time on the sphere that we initially started with, however, each time that I try to extract a new mask off of this initial geometry(starting sphere) that new object created from the extracted mask always has distorted geometry. When I try to use a grease pencil on this new piece of distorted geometry to delete the distorted sections, the hallow interior of the piece of geometry is revealed, or the line where the grease pencil was drawn becomes an elongated piece of geometry and takes the place of distorted piece of geometry. Either way, one of these two scenarios always happens when I try to edit the object created from an extracted mask.

Thank you Kent for the advice. I will keep trying until the grease pencil works, and I am excited to continue learning from this great tutorial!