Abstract Lampshade
In the surface space, use the loft tool and select the top and bottom curves. That will give you a surface that can be thickened to what ever size that you want.
A pure surface loft in one go will presumably fail in this case, as it looks like it will self intersect.
Go into the top sketch and draw a construction line(from e.g. origo) to a break point. Use the Modify->Break tool to split the curve in two. Do the same thing to the bottom sketch. Now do the two lofts.
Finally you can combine the surfaces and thicken them.
File>Export and then Attach your *.f3d file here if you can't figure it out.
(See Attached Shade.f3d file.)
You might need to drag the Point Mapping in your Loft.
@hpekristiansen wrote:
A pure surface loft in one go will presumably fail in this case, as it looks like it will self intersect.
The screenshot in the post from @wmhazzard would disagree with that statement.
You simply need to drag the Point Mapping as indicated above.
Or, you might need to sketch explicit Rails to map your points. (This can be done as 3D sketch.)
File>Export and then Attach your *.f3d file here if you can't figure it out.
Explicit Point Mapping Rails (3D Sketch).
As @TheCADWhisperer has already mentioned, the point mapping is off because a circle (analytical geometry) is used on the bottom and a spline is used at the top.
That will make it difficult for Fusion 360 to determine the point. mapping. If you use spline with that same number of spline control point that will help fusion.
Or, as already mentioned you can just drag the twist control handler, or you create a line between the end/start point and use that as a rail;.
Either way, this can be done in a single loft!