I'm very new to OpenSCAD and the forum. I have been watching this topic in the hope that it might shed some light for me. All I have got out of it is that boat hulls are not simple.
I have a trike

and want to make a velomobile shell over it, like this one.

I created a very basic outline of my trike in OpenSCAD

and added started playing with different shapes to add to the shell.

Apart from the pieces of ball (code below) I will need to use pieces of cylinders and probably a few other shapes.
//shell front top
translate ([-200,0,400]) // position
scale ([2,1,1]) // stretch x
rotate([0, 0, -90]) // rotate z
qtr_ball(380); // 380 outside radius
module qtr_ball(out_rad){
difference(){
half_ball(out_rad);
translate([-out_rad-1,-out_rad-1,(-out_rad-1)*2])
cube ([(out_rad+1)*2,(out_rad+1)*2,(out_rad+1)*2]);
}
}
module half_ball(out_rad){
difference(){
ball(out_rad);
translate([-out_rad-1,0,-out_rad-1])
cube ([(out_rad+1)*2,out_rad+1,(out_rad+1)*2]);
}
}
module ball(out_rad){
difference(){
sphere(out_rad, $fn=200);
sphere(out_rad-5, $fn=50);
}
}
Peter
FeetFirst.Bike