PTC Creo - Lattice Feature

PTC Creo has the feature called Lattice which are not in most of other leading CAD software provided. Lattice feature allow any shape of solid body convert into geometrically pattern, that are impossible or tedious in design manually. Which mainly allow to reduce the part weight keeping more or same strength while saving material cost. Although this part or lattice feature only can be manufactured with additive manufacturing technology.
Creo Lattice Feature
Lattice Feature

[@MrStickykey]

I noticed you put a shell extrude for these cutout areas, does this help with the generation of lattice structure? I have had volumes fail and wondered if this was related.+

[@vivekanandbhamare2138]

During splitting body only one surface getting selected. How do you select complete surface body?