Hello,
I think Art cannot be taught, it's a god gifted skill. A teacher can only improve the knowledge but your personal skills matter most.
Then you have the "Masters", they are the God gifted ones, they see things (and thus render their subjects) differently. They take it beyond teachers of the craft, it is in their hearts and souls, you would have better success to tell them to stop breathing than to demand they give up their art.
I didn't find the right solution from the internet.
References:
http://www.artistforum.com/sculpting/ca ... art-42265/
whiteboard animation