To turn on advanced rendering, set a check next to Turn on Advanced Rendering in the game options ingame.
Another option is to edit the options.ini file in the user data director
Open the file in a text editor like NotePad and look for the following line.
To turn on advanced rendering, set the value to 1. This means, if there’s a 0 right now, change it to 1, save the file and you’re done.