Hello All I need your help for this isuee. Here is what I want to make as 3D.There is chamfer 1.66mm x 1.66mm.I tried this.. but Autocad told me "Error ,Blend failed.. "but I do not know why at all...Here is starting point.First, I draw this line with Adobe-Illustrator. and output DWG file.and Open it....I tried with 3 way. 1) With Chamferedge  --> failed.2) With Blend only.. ---> failed...3) with Sweep --> failed.I hope Someone tell me why Autocad can not draw this simple shape..Is this limitation ??? Could you help me ?? here is cad file uploads/724730/shape1x.zipIf AutoCAD is not possible to draw it,How should I do ? Should I buy other CAD software to draw this only ?David.

I have had time to open/view your drawing.  You could try using AutoDesk A360.

Well if you're more concerned about the end result (may not fully satisfy your requirements however) rather than the process I was able to achieve the following.  It was somewhat involved.  Maybe someone else here with better skills can arrive at a solution with less work.  And, yes, it is a 3D solid.  I checked.

John Connor2017-05-04 12:49:38

Thank you , John.It is good : )I want to learn your step with AutoCAD.I tried many time "Chamfer" -> Loop -> Select some edge -> 1.6 -> 1.6 -> EnterCAD refused to make chamfer with  same error.Failed to perform blend.Failure while chamfering.How to avoid this error ? Please have me to learn your skill....David.

I did not use chamfer.  I basically used a series of profiles that I lofted separately then unioned them (there were three) together.  But first I had to use the SPLINEDIT command and turn the outer spline into a polyline.

Thank you , JohnI also make it with LOFT + some guides.but It is not beautiful than I expect.There is lot of NOT good surfaces.. This maybe limitation of AutoCADAnyway, Thank you !I will try other software too.Is there any recommendation ?

I'd try either A360 or Inventor.

Sorry about late reply, I hope it will help... That's not a limitation of autocad what you said, I think your model suffers from bad junctions, or curves in the model. "Cannot blend" error is usually connected with inaccuracies in your 2d shape, for example 2 curves  are not perfectly blended with another curve/line(tangent)  between them. You should do a little "repair" of your curve exported from illustator - fillet the straight lines with radiuses so it gives a perfect blend or flow between the curves.Even if you managed to get polyline from your closed shape or a region, that does not mean the CHAMFEREDGE command will work if curves are "badly" joined.Sorry I cannot open your attached file because I use ACAD2015. 

If naka hasn't fixed the problem by now (some 14 months later) then he had better change careers.