Thank you so much, the terrain is fixed now!! Shall I delete the post now that the problem is solved?

I looked at the ways to fix it through the steam launch options and they say Windows only. Is there another way to do it from there on my Mac?

To summarize my problem, which should be shown in the screenshot, terrain isn't loading in. Trees and stone load in fine, but the rest... I am playing on a Mac OS X Sierra. This happens every time I open the game, although it looks different each time.