Just installed SageMath from source.
Environment is
Distributor ID: Ubuntu Description: Ubuntu 23.04 Release: 23.04 Codename: lunar
running under Windows Linux System.
sage: x, y = var('x,y') sage: plot3d(x^2 + y^2, (x,-2,2), (y,-2,2)) Launched html viewer for Graphics3d Object
does not show any type of a three-dimensional plot. Two-dimensional plots work.
Regards,
Chuck... WB6YOK