Sweep / Loft but not parallel to cut a 'variable' chamfer

[garfieldQ2F8V]

I have a solid that is based upon a conic curve, one face of this I need to be chamfered but the angle of the chamfer must become progressively shallower as it follows the curve, then return to the starting angle on the opposite side of the part. 

I've tried all sorts - Loft / Sweep etc - I'm clearly doing something wrong but what ?

[TheCADWhisperer]

Attach *.f3d file here.

[garfieldQ2F8V]

Is there a specific vid related to this topic ?

Sweep only wants to cut using the same profile all the way around, loft refuses to do anything whether tried from an end or a face. I'd have expected loft to do this selecting the upper and lower line as rails but it doesn't.

I've attached the f3d but when looking at it please consider that when I started this drawing 2 years ago I was a real beginner and some things I'd do differently now but I'm reluctant to throw in the trash because of the hours expended.

[TheCADWhisperer]

I think that you will need more control geometry, but frankly, I would start over from scratch...

...if you zoom wayyyyy in here you will see some extraneous geometry that I suspect is not part of your true Design Intent.

[garfieldQ2F8V]

Then how best to start ?

I had to generate the initial 'sketch' from a pattern as I do not have access to the drawings for the original so I essentially had to trace the outline which was challenging in itself.

How would this control geometry be best included if I start again and what would you recommend - your image provides some clues but I'm learning as I go with Fusion and probably not using all the 'optimal' methods as a result.

I've studied lofts and sweeps amongst other things but they tend to be 'simple' symetrical examples.

I've another challenge and that's to create a 'random' surface across a face (to model cusions of all things) but that's for a different question.

[TrippyLighting]

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@garfieldQ2F8V wrote:

Then how best to start ?

Fully constrain and dimension your sketches. Otherwise it is easy to destroy your design by accidentally dragging on sketch elements in the viewport.

Name your sketches and delete those that are not needed.

[garfieldQ2F8V]

I shall try to do so - I will start again from scratch because I'm just fighting with this one all the time as that 'unrequired geometry' shows.