Baking ambient occlusion to vertex colors: What am I doing wrong?

I was able to bake the AO to the vertex color of the mesh follwing the infos here:

But the result is not what I was expecting:

Somehow the vertex colors at the angle are getting too bright, where they should be pretty dark.

Trying to understand what I did wrong, i created a new file, and baked it again to a two times subdivided default qube:
Somehow, the edges of the qube were unnecessary darkend.

Same or even weider Behaviour with triangulated faces:

I’ve found this tutorial:
But the output was still weird.

I’ve set up a simple test scene with three cutted qubes
Left: Baked to a texture UV -> Everything as it should be :slight_smile:
Mid: Vertex AO raytrace gather (again way too bright verts in the center)
Right: Vertex AO Approximate gather (weird darkend tris)

I was on the third google page, messed with all settings I had im mind, high and low gather settings, triangulated faces, smoothing, additional UV, World settings, tested it with 2.79 and 2.66 and still could not find a solution. (“Vertex paint: Paint: Dirty vertex colors” was interesting but still not what i’m looking for)
Does anyone have a solution or an idea?

Testscene: BakingAoToVertexColorTest.blend (820.8 KB) (2.79b)

I could not find a solution in the meantime. But I’ve found other tools and also how the vertex based AO baking process works. (Would take some time to implement it by myself)
I would really like to bake it with Blender, because I model and texture everything with Blender and it would fit perfectly in my workflow.
I hope there is a simple solution.