But I guess it is due to some missconfiguration in my retration settings or something with my extruder hotend assembly. I printed another part, which came out pretty ok for my experience, but still has the same under extrusion problem on walls after retractions. On small details, where there is no inner wall, the under extrusion occurs therefore on the outer wall. (second image, this is how it came out of the printer, except for the tree supports i removed)
The weird thing is, that i didn't have any stringing or blobing during the travel to the small "pillar". I do not have a clue where the missing plastic could have gone.
The problem is less present, when using Simplify3D, but this introduces other problems (Overextrusion on Layerstart, which I couldn't fix yet). Additionally my Cura profile is tuned better, and I'm used to it. As I said, I'm pretty happy with the quality of the part except for the under extrusion. Maby someone had this problem already and was able to fix it?
Thanks for your help.