If not already created put customAOVS.txt file in C:\Program Files\3Delight\maya
put in
#################################
float faceid “faceid”
color unused, float wireframe “wireframe”
##############################
the “color unused” part creates an alpha channel.
####### attach 3delight Geo Attribute to objects
switch on geometry > output faceid
############# render settings
under image outputs > add > custom variables > faceid and wireframe
face id > outlining > generate outlines using this layer
wireframe >outlining > Draw outlines in this layer
############ Other custom aovs
more info on custom aovs https://3delight.atlassian.net/wiki/display/3DFM/AOV+Selector