Select the stationary face.
Fusion 360 sheet metal flat pattern.
Sheet metal bodies with multiple radii curves or arcs in the sketch.
How to make flat patterns for rolled sheet metal designs.
To do that create the sheet metal part from scratch in fusion 360.
Go to modify flat pattern.
Only flat linear sections of sheet metal can be used as the stationary base face for a flat pattern.
Create a small flat tab somewhere on your design that can be cut off during manufacturing and use that as the stationary face for the flat pattern.
There was an unexpected problem with exporting the flat pattern as a dxf file.
An example of the procedure for a sat file is presented in the screencast below.
Link to vote for improved sheet metal tools in fusion.