The RIB for this image was created with the new plug-in. It shows the smooth shading effect of sending normals for each polygon vertex to RenderMan.
The best way to do curved surfaces is with spheres and spline meshes, but smoothed polygons are a good alternative if you are importing polygons from a DXF file.
The RIB for this image was created with the current plug-in. The polygons are clearly visible.