Hi Bruno, could you please post a 3DM model file with your curves in it so I can take a look over here?

But yes, curve blend in MoI and Rhino are probably not 100% exactly the same, there may be slight differences in how they apply the "bulge" factor.

If you have a kind of extreme case where there isn't much space to fit the blend in you're probably better off drawing in a control point curve to control things more exactly.

- Michael