I never took a class, but my 2nd job out of high school was working in a shop that made park trains (16", 24", & 36" gauge.). Started off sweeping, then to the mills. Once they found out I knew AutoCAD I was converting the paper drawings to ACAD in between pulling the handle. THen once I learned SolidWorks, I was converting from ACAD to SW. I can not tell you how much that has helped me as a mechanical design engineer. I'm always getting asked by even more experienced MEs to review things because I know how to make things. I also can't tell you how many parts I've viewed from newer ME's that have square internal corners in pockets and holes.