A highlight is caused when a small part of your 3D object reflects a lot of light (A hotspot), making it appears shiny.
(A highlight; is caused; T:when a small part of your 3D object reflects a lot of light) (a small part of your 3D object; reflects; a lot of light)
A highlight a small part of your 3D object
is caused reflects
T:when a small part of your 3D object reflects a lot of light
a lot of light