I have imported a surface model (modular back of the DrivAer model), and I would like to thicken it, because I have to create measuring points in it, so we can later test it in a wind tunnel. I managed to repair the surface, so it could be thickened, but I could only get the thicken command to work with 1 [mm], as the smallest radius of curvature is ~1 [mm], and thats not enough as the model is quite big. I tried creating sectioning planes, and using the intersecting curves command, then lofting it to the sides, but the splines, that the intersection curves create, don't seem to be conjointed, as if I close it up with two straight lines, it doesn't create and enclosed contour.

Has anybody encountered a similar problem to this, or does anybody have some kind of idea on how should I proceed with the task?

TL;DR: Thicken only works up to 1 [mm], I would like to have a thicker solid body.

Thanks in advance!

(I attached the model I'm working with, as well as the original .igs file)