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Otago Polytechnic Dunedin School of Art painting and print technical teacher Steev Peyroux said it was also one of art's more difficult disciplines.
"It's fundamental to every subject in art. The reason for that is it's about observational skill. The human figure is the most complex thing to draw."
He said artists could not get away with not getting it right.
"You just have to have the knowledge to be able to draw."
Mr Peyroux, who is also night class co-ordinator, said the polytech ran 21 classes a week with more than 200 students, learning everything from ceramics to jewellery and sculpture in courses that were open to the public.
Over the course of the year, there were about 80 people attending life drawing classes.
He said even abstract representation of the human form could not be done without knowing the fundamentals.
"The classic example everyone uses, Picasso, the founder of abstraction art in many ways, was an incredibly good draughtsman."
"It's that classic thing; you've got to know the rules to break them."
People's observation was how they interpreted the world.
"Drawing is representing that.
"And the thing about drawing the human form is we're drawing our own selves in many ways."
Some of the traps students fell into were getting "zoomed in" to a body part, working in high detail on a shoulder, for instance.
"They'll get round to the rest of the body and the shoulder will be way too small."
Another was "drawing what you think you know".
"We look at humans every day and think you know them."
Some students ended up drawing the body as they thought it was rather than observing what was in front of them.
"You have to go with what you see."
Tutor Madison Kelly said some classes were for beginners, but artists in the class the Otago Daily Times attended were more experienced.
One did engineering and cartooning, and others were from animation and design courses, who found skill in life drawing helpful.
Ms Kelly said the main goal of the tutor was to create an environment in which the model knew what they were doing, and to "focus on different things for different students".
Some students needed to work on the measuring and proportions, while others needed an external eye "not actually tied up in the act of drawing".
"When you're doing the drawing, it can be harder, sometimes, to see what's happening."