What I observed; The software website we worked on was tinkercad.com.  In Tinkercad we designed a coin and sent it to a 3-D printer.  A few coins had a ruff run but overall it was okay. As a class we were broke up into groups and one group designed the coin and one group observed and then we switched. While observing I asked a few students what they had trouble with and some said adjusting the  size of the object they were working on. Other than that it seemed like a pretty good experience tinkering and learning.