Ambient Occlusion not working at all?

[RonJambo187]

Like I posted in another thread: I'm very disappointed with the look of the vegetation. It seems to me the grass has no self-shadowing at all, it seems completely flat, like simple ambient shading.

Since the AO issue went unnoticed in the other thread, I decided to open up a new one.

I get the impression that ambient occlusion does not work: I can see no difference between SSAO, HBAO+ and deactivating it altogether. What puzzled me was, when I opened the Nvidia control panel and wanted to temper with the settings, it said under "ambient occlusion": "this feature is not supported by the application". How can this be?!

My graphics card is an Nvidia GeForce GTX 760, the game runs relatively smooth on ultra.
No other temporary game with AO I played so far is having such ugly "flat-shaded" vegetation (hell, even the grass in Gothic 3 looked better back then).
The vegetation objects themselves look good, just the shading is terrible (=nonexistent in my opinion).

[haticK]

There are some tweaks in here that will add shadows to vegetation:
http://www.geforce.com/whats-new/guides/the-witcher-3-wild-hunt-graphics-performance-and-tweaking-guide#config-file-tweaks

[RonJambo187]

Yeah, I tried these. But they don't change the actual problem: FoliageShadowDistanceScale for example adds some more bushes and trees that cast a shadow, but still the grass and other vegetation objects don't have any form of self shadowing.

I also compared the screenshots of this site that are supposed to show the game on ultra settings with my own screenshots from the same spot (the windmill near the starting village).
Although I run the exact same settings (checked the user.ini) the vegetation looks WAY flatter and washed out on my pictures, even the textures seem to have significantly lower detail...

This is not how it is supposed to look at all! The pictures from the geforce site are supposed to be actual game graphics, not some old PR-material, aren't they?