First thing that seems inconsistent is that manifold solids have to be changed to surfaces to be recognised as ruled surfaces, whilst open surfaces just get on with it. Next thing is the tool declares that conical surfaces ruled from a profile to a point don't appear to be ruled surfaces. If the point is trimmed off, unfold works. The result from many (most? all?) imported ruled surfaces is twisted, which I worked around by changing them to curves and lofting a ruled surface between the end curves. Where I filleted the faces of solids, some of the edges were twisted as well, which I worked around in the same way as I treated imports, by reducing them to curves and lofting ruled surfaces between the end curves. The tool doesn't recognise and unfold trimmed surfaces, so unusable for unfolding duct junctions or tube intersections. It also won't recognise and unfold a full cylinder, and also fails for cylindrical and conical surfaces that have longitudinal edges that aren't coaxial. The ol' "reduce to curves, ruled surface between 'em" workaround overcomes that. Another anomaly that I got was after subtracting a block from a cylinder, where the result had coaxial edges, sometimes the result was twisted.

A more general observation is that the unfolded layout can appear anywhere in the drawing. It would be a good thing if it appeared close to the ruled surface that it's associated to.

Edited by user Tuesday, September 13, 2016 4:54:31 PM(UTC)  | Reason: Not specified