> restart;

> z:=rho*cos(phi):r:=rho*sin(phi):

> x:=r*cos(theta):y:=r*sin(theta):

> rho:=2*cos(phi)*sin(phi)^2:

> c:=plot3d([x,y,z],theta=0..2*Pi,phi=0..Pi/2,scaling=constrained,grid=[20,50]):

> c;

> with(plottools):

> vrml(c,"c:/040/12/12-9.wrl",background_color=white):

>