I tried making basic mockups in Blender 3d, then printing out on paper just the shading. Then I drew on the paper with a rapidograph. The technique shows promise but I need a lot of practice to make it work.
They were a little stiff compared to the looseness of a totally free hand drawing. Perhaps warping the model a bit.
Or not trying to trace the rendered image (i.e., print out the image, prop it up as an artist's model, then manually draw on a blank piece of paper while glancing at the model).
@nyrath@thisnorthernboy Yeah, don't trace, just mark the relevant spots if you need that, and let the hand flow. Tracing always make your brain just follow the line instead of focusing on the shape.