Hi @Bruno_Suraski, you almost got it right and splitted with the plane. But note what
_GCon reports. It tells you it is G1 but the tangents slightly differ because your document angle tolerance is set to 1 degree. So everything below that is reported as G1, but it is not:
Usually you can get the intersection point (where the bisector starts) by using
_DupEdge on the fillets and intersect them. btw. the plane orientation can also be not perpendicular to the bisector, it is just important that the plane origin is where the fillets intersect, because only at this point the fillets are tangent to eachother.
I’ve proceeded using Sweep2, and used the joined fillet sections as first cross section and the bridging line in the middle as second cross section. After this you get a result which explodes in 2 surfaces. If it’s not looking clean enough, match each of the exploded surfaces on 2 sides. Eg. the upper piece of the sweep is matched to the cutting arc of the upper fillet and Rail 2 in your image. Use
_MatchSrf _MultipleMatches for it. I used these settings:
Then don’t just mirror it, i used
_Symmetry Continuity=Smooth to make the other side…