Can parts that have warped (after being printed) be un-warped? I have an on-going project to build a large lampshade in the shape of a geodesic dome. It's made of 3D printed frames that will be covered with rice paper. I printed the parts in PLA over a month or so, but then had to ship them from Europe to Japan due to moving house.
Unfortunately, when they arrived a lot of them had warped quite badly. In retrospect they weren't packed very well, and they probably got quite hot while travelling through the tropics in a shipping container.
I'm wondering if there is any reasonable way to un-warp parts that have warped in this way. Specifically, if I heat them up again, will they go back to their original shape, or will that just make it worse?
Here's a photo to show what the parts look like. The problem was a lot more obvious before I assembled it, but I didn't think to take a photo - here you can see that some of the edges aren't dead straight, but when they're not clipped to the other parts they're a lot worse. The edge of each triangle is a bit less than 20cm in length.

I'd really appreciate any tips. It'd be a shame if this project ended up not looking perfect after so much printing time.
PLA stays a thermoplastic in printed shape. And as you saw when unpacking your things, tropical heat and force are enough to get a lasting deformation. Other people had PLA prints ruined from having them sit in the car, I had seen deformation on a purple print I had let sit in the sun on an edge.
This also means that the reverse is true: under load to shape the part and some heat you can try to unbend parts. A hairdryer air of about 60-80 °C, which is more than enough to make PLA formable.