Forces to produce wall-painting (6)
I believe the answer is:
fresco
'wall-painting' is the definition.
(I've seen this before)
'forces to produce' is the wordplay.
'to produce' is an anagram indicator.
'forces' anagrammed gives 'FRESCO'.
(Other definitions for fresco that I've seen before include "Work of art" , "Painting using watercolours on plaster" , "Picture painted on wall or ceiling before plaster is dry" , "Mural painting" , "Forces (anag) - wall painting" .)