Happy Father's Day!

I saw those! The old "stereo-lithography" method with a modern "inverted" twist I guess. That was pretty new when I was in college. We took a tour of a facility that had one, it was a huge 60"x60"x30" vat that had a bed that raised and lowered in this vat of resin. The table would lift to -.1mm depth and a laser would trace a shape on the .1mm of visible resin, hardening it instantly then the bed would dip down .1mm and the process would start again, building upon the hard layer under it. It was incredibly time consuming (runs would take all night and more) but it was state of the art back in 1990. It had a ripple sensor so if there were any seismic activity (trucks rolling by, tremors, etc) it would pause until the resin level was completely flat again. It was all prototype work, nothing was tough enough to actually use. They were making operating room equipment knobs in different shapes to see what would work best with bloody gloves at the time we visited.