I imported an outline from Adobe Illustrator - actually the shape of a hull side panel. I then turned it into a thin solid object using Solid>Extrude Planar Curve>Straight and coloured it in the usual way via Object Properties.
When rendered in the Perspective viewport, it appeared - as intended - as a thin solid object with all faces in the selected colour. However, when I tried to bend the object using Transform>Bend, the rendering on the two main faces disappeared leaving only the edges coloured.
I have attached a file showing the two stages - creating of solid rendered object, then attempt to bend a copy.
Any thoughts on the possible cause of this apparent anomaly and any suggestions as to how to get round it would be welcome.
It was hard to find but there is a screw up in the imported curve.
Explode the original curves and turn on the control points. Zoom in on the counter notch. You'll see the horizontal curve doubles back on itself. One of its points extends beyond the end. Delete this extra point and Join the curves back together. Then it will Extrude, Bend and Shade as expected.
The curve was causing the surface definitions to be self-intersecting making them impossible to mesh.
Always closely inspect imported geometry before pushing ahead with your surfacing.
John Brock - Rhinoceros Tech Support
Seattle - USA