MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
Ok, cool. I'll try and print a load off in the morning and pick the best ones.
Regarding the lens, yes, it's the infill patter that gives the effect.
I took your noyau_lentille file, cut it down in Slic3r, then printed with 40% honeycomb infill, 1 bottom layer, 4 top layers and 4 perimeters.