Modelling refers to the demonstration of a behaviour so that it may be learnt vicariously by the client.
See also:
"Modelling" is in the CPC Code "3544"
  Modelling pastes; "dental wax" or "dental impression compounds"; other preparations for use in dentistry with a basis of plaster; preparations and charges for fire-extinguishers; charged fire-extinguishing grenades; prepared culture media for development of micro-organisms; composite diagnostic or laboratory reagents n.e.c.
"Modelling" is in the HS Code "3407"
  Modelling Pastes, Including Those Put Up For Children`S Amusement; Preparations Known As Dental Wax
Other /More definition:
Modelling refers to the demonstration of a behaviour so that it may be learnt vicariously by the client.