How can I plot a pipe elbow in matlab?

I am trying to plot a pipe elbow in matlab with toroidal coordinates (r, theta, phi). Where x = 2*cos(phi)+r*cos(theta); y = 2*sin(phi)+r*cos(theta); z = r*cos(theta). r = 0-1; theta = 0-2*pi; phi = 0-pi/2. I was trying to do this with the following code: clear; r=0:1:30; theta=linspace(0,2*pi,30); phi=linspace(0,pi/2,30); [phi,theta]=meshgrid(phi,theta); x=2*cos(phi)+r*cos(theta); y=2*sin(phi)+r*cos(theta); z=r*cos(theta); mesh(x,y,z) view(135,30) axis tight box on xlabel(‘x-axis’) ylabel(‘y-axis’) zlabel(‘z-axis’) Do you have a better code to plot this pipe bend/pipe elbow? From this I will need to do a velocity profile and temperature profile based on the Navier Stokes PDEs. Thanks, David