Hi
Sage8.0.
there is a difference Between SageMath under VirtualBox Linux VM : Nice graph, or SageMath under W10 :no graph at all when executing this code in notebook.
x, y = var('x y')
W = plot3d(sin(pi*((x)^2+(y)^2))/2,(x,-1,1),(y,-1,1), frame=False, color='purple', opacity=0.8)
S = sphere((0,0,0),size=0.3, color='red', aspect_ratio=[1,1,1])
show(W + S, figsize=8)