> an arc of an half circle of course :)

Yup, but although it is similar, it is not the correct shape. A sine curve is kind of more of a lump, it doesn't have the exact shape of an arc.


> K3Dsurf seems the best It has an OBJ export
> Rest to found a transform obj -->nurbs :)

This may be a difficult transform. But didn't Amapi do something for this when exporting polygons to IGES? I thought that some wireframe line curves came through. So that is one possibility.

But it looks like K3Dsurf only does surfaces and not curves - for doing curves possibly that other one will work.

- Michael