3D Systems CubePro Manual page 21

INF Supports
INF material is effective for supporting nylon parts containing inner chambers, moving parts
and multiple small overhanging features. For larger overhanging features or other parts
that are subject to becoming warped, Manual Supports should be used to help anchor
corners. In addition, Manual Supports should be used with INF Supports to maintain the
smooth down-facing surfaces of parts as well as detailed and intricate features of parts
requiring support. In addition, INF supports provide smoother bottom surfaces than
standard nylon supports.
Select INF from the Support Material drop down menu in the Build Settings utility.