Ken,
Unfortunately even Alibre Expert has restrictions on the shape of the profile and as far as I can tell only straight lines and circular arcs that are tangent are allowed, curves with inflection points are not allowed. Hopefuly in the furure that will be changed. There are software packages for circuit analysis and pc board layout that have all features activated with restrictions as to the number of nodes that can be analyzed or the number of layers etc. That would be nice to have in Alibre as well and as I understand the personal version does not allow importing 3D figures.
I understand the financial concern, before I retired, more or less, I would buy just about anything that looked useful and now I buy only what is needed. A friend mentioned a relatively inexpensive sheetmetal program that could probably do what you want, I'll see if he still has the program.
Good luck with the project.
Jim C