I am using Blender 2.90 on OS X.
Sometimes just writing it out to everyone helps me resolve the issue.
I created a path in Affinity Design and imported it as SVG. I do that a lot.
I want to make a paper clip, and bevel along the paper clip path.
The problem is that the paperclip is perfectly flat. See image. I found an explanation, BUT it does not make sense to me (maybe I am tired):
The trick is that the shape you want to extrude along the curve must be in the local XY plane of the bevel object. In fact, before extrusion takes place, the contents of the bevel object are projected to the XY plane of the bevel object. It is the same as if you had switched the Shape of the bevel object to 2D. If your extruded shape is on the local XZ or YZ plane of the bevel object, then it will be reduced to a line when projected to the XY plane, and this line will be extruded along the curve, resulting in a flat extrusion.
This does not make sense to me, nor is it addressed in tutorials I have seen. I have done this before, but maybe it is because my path was imported as SVG?
Link to file removed.