Hoping you experts can help me out with a problem please. I attach a picture of some work in progress. The section of tubing between the red lines has a constant internal diameter of 2.75" and a tapering external diameter (3.45" down to 3.21"). The tube incorporates an 8.5R bend in one plane only.

So far I've tried various means of creating this tube:

1. Create straight tapered tube using revolved tapered profile and then attempt to bend using Flex tool. I love the control you get using the revolved profile but the Flex tool is truly horrible and is hard to get the exact result I require. I think the Flex tool might be great for concept work but not for accurate engineering.

2. Create straight parallel tube using extruded profile, apply draft angle to achieve tapered tube. Use Flex tool to bend. Same issue as above.

3. Create curved parallel tube using swept circular profile along curved path. Attempted to apply taper using draft but I just get errors. Is this even possible?

4. Create curved and tapered tube using lofted profiles and guide curves or the boundary tool and guide curves. This does the job but is computationally intensive and I believe less accurate than a swept circular profile. I've analysed sections of models produced using lofting/boundary before and found strange surface features or out-of-true sections.

So the question is, am I missing a trick or is the lofting/boundary solution the only way to go? If option 3 worked then it would have been perfect and much simpler than all the rest. Perhaps I can erode the surface of the tube to form the required taper in another way? Even if the Flex tool worked, I much prefer starting with an accurate drawing and revolving/sweeping etc. rather than trying to bend the straight tube to fit the drawing.

Any help you can provide would be very much appreciated. I'm getting pretty frustrated with this!

Thanks,

Dave