As we all know, vegetation is any average/poor GPU's worst enemy in this game, so an option to simply disable the vegetation in maps would be pretty cool.
This is already possible, turn off ground cover and forest to fully disable. Enjoy your very boring terrains.
Step one: Open the world editor (F11) Two: Find the symbol that looks like an eye, on the top toolbar. click that. Three: Click the second tab that reads "Visible" Four: scroll down and find "GroundCover". click it and grass and such will turn off. This will boost fps. If you need more turn off "Forest" as well. a word of caution with this is that the objects still exist and you can/will collide with them. you just can see. them. so fps will improve while playability will not. also, "forest" includes rocks and shrubs. hope this helps!
there are "better" ways to remove the vegetation which will also remove the clipping but alter the map and so ask you to save or you will have to do it again. 1. delete the complete vegetation folder of the scene panel, this will remove all vegetation related objects. or 2. enter the vegetation editor and select trees by hand to delete them manualy one by one, this makes you able to keep rocks for example.