Well if you want to get dirty and not deal with design, build a vacuum former. Shop vac, perf board, 2x4 or 1x2 frame and whatever rigid for a backer. Build the frames out of screen door frame pieces, and binder clips to close them. Polystyrene sheets are cheap af $.05 or less at any plastic supplier. Never been to a plastic supplier? I guarantee theres one relatively near by in whatever is your closest major city. Use your oven to heat the plastic. Turn on the vac, pull out the plastic when it droops, slam down quick… perfect part. Lots of videos on youtube. Adam savage does a few on the process. Lots of nuance to the process to get really good pieces but for cheap, quick and good its hard to beat. Oh yeah the whole stormtrooper cosplay scene has done a lot of work on the setup, most definitely lots of improvements that I’m glossing over but like all rabbit holes its pretty deep.

Adam Savage’s guide to vacuum forming https://youtube.com/watch?v=lTy8tsZzT_Q&pp=ygUaYWRhbSBzYXZhZ...

First page I could find for the diy stormtrooper costume process https://www.studiocreations.com/howto/stormtrooper/index.htm...