How to model a spout? (struggling with sweep/loft)

[Charlie-83]

I want to model something like this:

I am having two issues:

First, I cannot find a way to combine the sweep and loft operations. Using the sweep operation, I can create a tube that curves nicely: however both ends of the tube must be the same shape. Using the loft operation I can create a tube that transitions nicely from circle to rectangle, however, it then follows a straight path and involves no curve.

My second issue is in using sweep/loft with profiles that have a hole in the middle.

Take the following program

start = cq.Sketch().circle(5).circle(4, mode="s")
end = cq.Sketch().circle(6).circle(5, mode="s")
result = cq.Workplane().placeSketch(start, end.moved(z=10)).loft()

I would expect this to produce a tube which grows in the z direction; instead it produces a solid object.

My alternative approach would be to deliberately make a solid object and then use shell to turn it into a tube. This would work for the simple example I gave above but doesn't work in more complex scenarios particularly when lofting from a circle to a rectangle: the shell just fails with BRep_API: command not done

[adam-urbanczyk]

I'd try the following approach:

from cadquery.func import *

spine = spline(((0,0,0),(2,0,3)), ((0,0,1), (1,0,0.3)))
c = face(circle(0.5), circle(0.4))
r = face(rect(0.2, 1), rect(0.1, 0.9))

res = loft(c, c.moved(spine.locationAt(0.5)), r.moved(spine.locationAt(1)))