Use perspective guides when giving volume to the concept
I’m now happy with the design so I can start showing volume. I select a point of view and trace a simple two-point perspective grid that helps me to define depth. Following the grid, I can now draw the receding far side of the object in correlation with the near side. I’m not tracing and calculating everything because at this angle I can get away with some guesswork, but having the perspective grid makes life much easier.