Artwork includes model foot able to be sculpted (7)
I believe the answer is:
plastic
'able to be sculpted' is the definition.
(something plastic can be sculpted or shaped)
'artwork includes model foot' is the wordplay.
'artwork' becomes 'pic' (picture).
'includes' is an insertion indicator.
'model foot' becomes 'last' (shoemaker's model).
'pic' placed around 'last' is 'PLASTIC'.
(Other definitions for plastic that I've seen before include "source of credit" , "Scalp it badly to make a synthetic material" , "(Originally malleable) material" , "Capable of being moulded" , "Clasp it (anag.)" .)