Arrakis was mostly filmed in a desert, how did it not feel real? The CGI in Dune was pretty decent IMO and the highlight for me was the ornithopters wing flapping. The motion blur of the wings was simply amazing.
It is noticable that it’s not filmed in a hot place because the actors are never sweating, they move too fast, their skin doesn’t have the color and texture of a strong tan, they don’t seem affected by transitioning from hot to cold, they touch sand with naked hands, etc. Compare with western movies that are actually filmed on location, they somehow feel like they’re filmed on a hotter planet than arakis
EDIT: seems that most of the scenes in the desert filmed in situ were also in relatively cold deserts as the filming crew is wearing down jackets