In V12, individual arcs can be grouped into a spline using the Group elements into a spline function (feature for demo purposes only, not released)

If a component contains a curve with a variable radius, you have to approximate this curve using many individual arcs (arc over 3 points on the circumference [Arc through 3 points on circle], see following figure). The spline feature now makes it possible to export not the individual arcs, but the grouping of these in the spline. This reduces the susceptibility to errors during export, especially when using the blend feature. In addition, the display in the 3D view is more accurate.

First single arcs are drawn and then the spline feature is used.