Comparison of different graphic settings in few in-game locations.
Disclaimer
All screenshots were taken without restarting the game, so textures on low settings might be a bit worse in practice.
Forest, Morning, Clear
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Jungle lake, Afternoon, Heavy rain
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Autumn Forest, Afternoon, Cloudy
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Mountain base, Morning, Heavy snow
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Canyon, Noon, Clear
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Mountain river, Afternoon, Heaby snow
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Island base, Afternoon, Clear
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Desert oasis, Noon, Clear
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Mountain river, Noon, Clear
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Autumn forest, Afternoon, Light rain
Ultra:
High:
Medium:
Low:
High:
Medium:
Low:
Thanks to Ragvard Grimclaw for his great guide, all credit to his effort. you can also read the original guide from Steam Community. Enjoy the game.