I call
x, y = var('x y')
plot3d(sin(pi*((x)^2+(y)^2))/2,(x,-1,1),(y,-1,1), frame=False, color='purple', opacity=0.8)
is called web browser with file:///home/andrzej/.sage/temp/50-5B-C2-D6-5C-BF/281710/tmp_0jkh7v0l.html but nothing further On Firefox nothing, on Chromium nothing I have Fedora with Cinnamon (installed from Fedora-Cinnamon-Live-x86_64-35-1.2.iso)