Stack a few circles, divide each into points, join each set of points into a polygonal ring, and loft one surface through all the rings. Along the way the data grows into a tree, and you will see why Loft needs Flatten.

A tapered loft through four hexagonal rings

Reference: choose Examples  Lofted rings (data trees) on the canvas toolbar to load the finished definition.

Build it

  1. Place five Number Slider components:

    • Rings: 4 (2 – 8), Decimals 0

    • Radius: 20 (5 – 40)

    • Taper: -3 (-8 – 8)

    • Spacing: 12 (4 – 30)

    • Points: 6 (3 – 16), Decimals 0

  2. Place a Series (Sets) for the radii. Wire Radius → S, Taper → N and Rings → C. It produces 20, 17, 14, 11.

  3. Place a second Series for the heights. Wire Spacing → N and Rings → C. It produces 0, 12, 24, 36.

  4. Place a Circle (Curve). Wire radii Series → R and heights Series → Z. You now have four stacked circles. Turn the Circle’s Preview off.

  5. Place a Divide Curve (Curve). Wire Circle C → C and Points → N.

  6. Place a Panel and wire Divide Curve P → Panel.

  7. Place a Polyline (Curve). Wire Divide Curve P → V, then use Set value… on its C (Closed) input to set it to True.

  8. Place a Loft (Surface) and wire Polyline Pl → C.

At this point Loft is red. Hover over it: "A loft needs at least two section curves".

  1. Right-click Loft’s C grip and tick Flatten. A yellow F badge appears next to the grip and the loft appears in the 3D view.

The finished tree definition

What is happening

Follow the paths in the Panel:

Step Data Why

Series

{0;0}: 4 numbers

A list output: one list, in one branch.

Circle

{0;0}: 4 circles

Item access: four runs, collected in the same branch.

Divide Curve

{0;0;0} … {0;0;3}: 6 points each

A list output: each run (each circle) gets its own branch.

Polyline

{0;0;0} … {0;0;3}: 1 ring each

List access: one run per branch, one ring per branch.

Loft, without Flatten

error

List access: one run per branch, and each branch holds a single ring.

Loft, with Flatten

{0}: 1 surface

Flatten puts all four rings into one list first.

The wires from Divide Curve onwards are dashed because they carry a tree with several branches.

Things to try

  • Drag Points to 3 (triangles) or 16 (nearly round), and Taper to a positive value to flare the shape outwards.

  • Right-click Divide Curve’s P output grip and tick Simplify. The paths in the Panel become {0} … {3}; nothing else changes.

  • Add a Cap Holes (Surface) after Loft to close the top and bottom: the open surface becomes a solid you can bake.

  • Untick Flatten again and add a Graft to Divide Curve’s output instead: now every single point gets its own branch, and Polyline fails for the same reason Loft did.