14-83 Trolley was the last assignment of the first semester if DDGT. By this time I had learned enough of the Inventor program to be proficient. Though this was the last assignmnet of the semester, I was not done learning. 14-83 Trolley was a great assignment for me to learn about sub-assemblies. A sub-assembly is a collection of parts assembled separately from the main assembly. As you can see, the third picture is an example of a sub-assembly that will need to be assebled twice to create what is displyed in the first picture. I learned how useful it is to insert sub-assemblies into an assembly file, how to call out the sub-assembly in the drawing and parts list, an how to import standard hardware from McMaster-Carr into an assembly.