Hey Mala,
I made a couple brief videos with your model and geometry to give some insight as to what you are looking for.

Here is one that shows the main culprit. But I also use this to show you "rebuild" and also talk a little about a common error made in "adhering to some unrealistic tolerance"

The CAD modeling will model things to pretty tight tolerances. even at unrealistic levels. Think a microscope on a razor blade. At some type of zoom, the sharp blade will look like the edge of a rock!!!

So applying your understanding of what may be needed (A welder fills in gaps on pipes) you can adjust expectations to meet the real world and get great results!

Here is one more. In the first video i left it with one area still showing error or non satisfactory results.

I found it and fixed it (Just quick and dirty. may need more thought to fix)

Wanted to show you...

Hey Burrman,
I'm doing very well with that. I'm going to focus more on the micro-level distortions that I've ignored up to now. I'll get around to it again this week. With the impulses, it should work very well. Thank you very much for your suggestions...

You’re welcome Mala!

Good luck….