[Feature Request] Support non-rectangular fin cross section in 3D view and OBJ export

[RocketMan3D]

While using Openrocket, I have observed that although it is possible to simulate fins with rounded and airfoiled shapes, they only appear as a square cross-section in the 3D view and .OBJ exports. It would be helpful to be able to quickly identify the fin shapes that are being simulated and to export other shapes for 3D printing. I understand that this might not be a simple task, so even if it is not visible in Openrocket, it would be great to have it in the .OBJ files.

[SiboVG]

Partially addressed in #2419.