Hi suman, here's an example of the kind of thing you'll need to draw on the left here - here I've drawn a path curve starting in the Top view, and then turning on its control points and adjusting them (particularly in the z direction to adjust their height), to get a sort of looped path curve. Because of the edits to the points in the Z direction the path curve also goes up and down, it's not just a 2D flat curve.

Then in order to control the sweep you will probably want to place several line segments along the path and these line segments will be used as the profile curves for a sweep. Make the line segments all copies from a single one so they're all the same length and adjust the rotation of any one of them by selecting it and running the Transform > Rotate > Rotate Axis command. The "Rotate axis" command asks you for a line for the pivot to rotate around, make sure both "Straight snap" and "Object snap" are on so that you can make that rotation axis line snap on to the path curve tangent so you can rotate the lines around the curve tangent at their base points.

This is all some pretty advanced 3D editing techniques and so it may take you some practice to get used to building 3D curves and editing the rotation of lines along a 3D path like I've described here. Also it can help to use History - to do that do the sweep and then edit the path and/or lines after the sweep is in place, then the sweep will update.

The way I did it, is I started with just one single line at the start of the path and did the sweep, then compared the banking to your desired screenshot and added in some more key lines in areas where the default banking was not very close to the kind of banking that you wanted.

Now with this surface in place you can use "surface to surface" flow to apply deformed shapes on to it.



- Michael