Thanks for the suggestion by the question. I am close to finishing a multiform geometry (Open source ).
A test resulted in the following
Not yet perfect!
function curvedArrowCenterline( h ) {
return { x: 0.1 * Math.sin( pi * h ), z: 0 };
}
function arrowOutline( h ) {
return{ y: h < 0.9 ? h : ( h === 0.9 ? 0.8 : h ), r: h < 0.9 ? 0.1 : ( h === 0.9 ? 0.2 : 0 ) }
}
UPDATE
Multiform geometry is easier than my Addon. Produces almost infinite many time-varying geometries with functions
It is not a real space curve, but only a horizontal offset of the layers. So a shear per height segment.
In the addon, it is a correctly bent cylinder. However, the arrowhead is not centered due to the height offset. You can create the arrowhead separately and form a group.
The best solution is certainly a specially created geometry. 