For anyone else having issues with the addon on 2.78, for some reason, you absolutely CANNOT use the numpad to change the ...

For anyone else having issues with the addon on 2.78, for some reason, you absolutely CANNOT use the numpad to change the view or the addon won't work properly. It will not cut properly unless your viewport specifically says "User Ortho", and it will not work properly in ANY view if you're trying to use grease pencil lines drawn in one of those views.
  • Kent Trammell replied

    I've answered so many questions about the Sculpt Tools UI not working properly, especially Grease Cut, and I just don't get it. I'm not experiencing the same issues that keep getting reported.

    See here I'm using 2.79 in perspective view, noting grease pencil is set to "Object" mode instead of Scene:

    Granted the addon has *always* been finicky with only a 50-60% success rate for grease cut. But do it enough times and it always works for me eventually. I know that ideally it would work perfectly, but hey, it's a free tool that isn't developed anymore. Either don't use the tool or be appreciative that it works at all.