The Su-57's design emphasizes frontal stealth, with RCS-reducing features most apparent in the forward hemisphere; the shaping of the aft fuselage, the seams between parts, and rivets are much less optimized for radar stealth compared to the F-22. However, during MAKS 2019, some observers noted that the craftsmanship of the fuselage was finer than expected from Russian aircraft and looked smooth despite the rivets. The second serial production Su-57 also seemed to have a significantly better tolerance on its skin panel than the previous prototype.