Then i made a bend like Surkål want's.
In "E" line the Y value cant be 0, it need a tiny little value, else the bended part will twist.
I'm happy i dont work with this kind of stuff, house ( rectangles and triangles) are more easy and fun
The ide'a about double point in the end, did not work, and the same with "Booling" it before bend, not work.
Thickness or Sweep did not made any difference.
NB!! The curves in 2D profile is not very "flexible" as it was only for having some curves in it, before bend
Example under here work.
L =Parameter ("Length",200, LINEAR);
W =Parameter ("Witdth",75, LINEAR);
T =Parameter ("Heigth",4, LINEAR);
D1 = ((W/6)*5);
Profile = Polyline(Point(0,0),Point(L/2,0),Arc1(L/2,D1),Point((L/4)*3,W/3),
SP = RotateY(Polyline( Point(0,0),Point(T,0)),-90);
SW = RotateX(Sweep(Profile,SP),-90);
E = G3Bend(SW,Point(L/3,0.0001,0),Point(L/3,0,W),45,5,0);
F = RotateX(E,90);