Thanks very much for your reply Laurent
It is easy to crash the new version but if you stick to the tutorial it should be very stable so treat anything outside of the tutorial as a bonus if it works New tutorials and updates coming soon but the current version does allow anyone to develop their artistic skills modelling a 3d head in your own style. It should be safe to insert extra lines in your head where you want more control so long as you do not try to divert your inserted line differently to how I show in the tutorial. Will be more robust with future updates,
regards