Use Sweep to push a profile along a curved path (springs, hoses, grab bars) and Loft to blend between two different profiles (funnels, fairings, round-to-square ducts).
Helical Coil Spring - a classic sweep. A small circle is swept along a helix path to make the spring wire.
A Sweep pushes a 2D shape (the profile) along a curved line (the path). Imagine squeezing toothpaste along a bendy line - that's a sweep.
Sketch the curved line (or 3D helix) the shape will follow. This is what decides the final shape.
Sketch the cross-section on a plane at the start of the path. Keep it simple - a circle usually works.
Pick the profile, pick the path, click OK. The CAD software extrudes the profile along the path.
If the path bends sharper than the profile's radius, the shape will self-intersect. Ease the curve or shrink the profile.
A Loft blends smoothly between two or more different profiles on different planes. Think of stretching a rubber sheet between two cardboard cutouts at different heights - that's a loft.
You need at least two. All profiles must be closed loops on flat planes.
Curves that guide the edges of the loft so the blend doesn't bulge in weird places.
The CAD solver works best when matching profiles have similar corners - e.g. all squares, or all circles.
The shape follows a known path and the cross-section stays roughly the same all along it.
The shape changes shape along its length - not just position. Round to square, big to small, one shape to another.
You need to model an HVAC adapter: a round duct on one end, a rectangular opening on the other. Which operation fits?
Build two shapes that extrude alone can't make: a coiled spring and a funnel.