plot3d orthographic projection

[david.g...@gmail.com]

When I specify orthographic projection in parametric_plot3d it doesn't work--still shows perspective:

t=var('t'); r=vector([t*cos(t),t*sin(t),t])
parametric_plot3d(r,(t,-2*pi,2*pi),color='red',projection='orthographic')

Am I doing something wrong? Is this broken? I normally use cocalc in docker, but I've also tried cocalc.com, same problem.

Thanks,

David