I am trying to export a png of the pcb in 3D Viewer and
what I get is only a part of the 3d image somehow distorted.
I am running KiCad 5.1.4+dfsg1-1, release build, on Debian testing (bullseye)
Nouveau has a few known issues with memory mapping. You might try the debian nonfree repository and install the nvidea-supplied drivers. I suspect that this will fix your issue.
I had problems with sddm (I got black screen on boot), yet I managed to login
by simply typing my passwd and pressing “Enter”.
kde-plasma seemed somehow broken (I had no panels, no apps menu,
just a black screen), but pressing “Alt+F2” and typing “in the void”
I opened Konsole and KiCad (standalone and from inside Konsole).
Pcbnew won’t open at all, and when I started KiCad from Konsole
I saw an error message mentioning GLK something.
I went back on nouveau…
I also installed KiCad in a win10 vm and 3d viewer works out of the box
considering exporting images.
Anyway I believe my system is kind of problematic and I will stick to a solution
including vrml exporting and blender rendering or simple screenshots, until I get
my new graphics card.