I use a program called Xara designer pro,. but you could also use Photoshop or (I think) paint-shop pro, and Gimp, since they all have “pen” tools to allow you to draw vector line shapes.and should be able to export as EPS
but… you don’t “need” to do it that way, it’s just a quick way to import the shape.
You can draw directly in the spline modeller in Carrara, and you can refine the shape using the little bezier handles on each vertex.
Once the basic shape is created,. you can adjust the extrusion depth by adjusting the default line on the floor, and you can Add bevels,. or you can convert it into a Vertex model,. instead of a spline,. then edit it further in the vertex modeller.
it’s just a quicker way to get that basic shape, without the struggle.
Another way would be to use a “path Sweep” in the vertex modeller,. you’d make a rectangle, and then a curvy line shape.
You’d select the rectangle,. then click on the Path sweep tool,. and then select the curvy line,. and it’ll make a new shape by extracting the rectangle shape along the curvy line path.