Having recently driven the Ring, both Nordschelife and GP track (full layout) for a handful of laps each - after learning the tracks from close to a hundred GT5/GT6 laps on each - and I will say that rendition in the game is actually pretty well done. Yes, it is obviously very difficult to replicate all aspects of a live track fully, e.g. tarmac condition, bank, curb appearance, run-off, outskirts of track etc., and additionally how weather and seasonal conditions change the appearance of track sections. And of course, some of the corners and bends have to be approached fairly different in real life conditions compared to the games, as slight bank/incline and track surface variations not present in the game greatly affects the handling of a car going 200+ KPH. But still, all in all, both tracks are reproduced in a life-like manner closely resembling the real deal. Not only was the preparation extremely valuable for my driving experience, but when I remember my real life session my memory occasionally mix up sections of the track with my in-game sessions. 
Go check some on-board videos to see the slight differences, and realize that the developers did a pretty well executed job to model two of the greater and more challenging circuits in the world. And I know this goes for most of the other tracks as well, although not yet having had the chance to drive any of them except parts of the Monaco roads in real life.
Go check some on-board videos to see the slight differences, and realize that the developers did a pretty well executed job to model two of the greater and more challenging circuits in the world. And I know this goes for most of the other tracks as well, although not yet having had the chance to drive any of them except parts of the Monaco roads in real life.