Geometry & 3D node
Sweep
Carries a profile along a path — a circle along a line is a pipe, a rectangle along a spiral is a ribbon, any outline along any curve is the general case. Both inputs are ordinary point clouds, so the profile can come from Path, Triangulate or a tracked outline and the spine from Path, a hand or a particle trail. The frame is parallel transported rather than derived from curvature, so a straight run does not spin and an inflection does not flip; a closed path has its residual twist spread out so the seam meets. Twist turns the profile along the way, Scale Start and End taper it. Segment Start, Length and Offset take only PART of the spine and slide that window along it: park it with Start, drive Offset from an LFO and the piece rides the path. Offset counts LAPS and is unbounded — 0 to 1 is one circuit, 1 to 2 the next, for as long as you feed it. Several Sweeps on one spine with different Starts and a shared Offset are carriages on a train. On a closed path the window wraps round the seam, and taking part of a loop opens it, so the piece caps like any other open sweep.
Inputs
| Port | Type | Default |
|---|---|---|
| ProfileThe cross-section, carried along the path. It is read in XY — a circle here makes a pipe, a rectangle a beam, a glyph outline a moulding. Cable it from Path, from Triangulate’s outline, from a tracked blob; nothing here knows or cares which. | structure | — |
| PathThe spine the profile travels along. Any ordered cloud: a Path, a hand’s motion, a particle trail. The frame is carried forward from point to point rather than derived from curvature, so a straight run does not spin and a bend does not flip. | structure | — |
| OrderHow the profile points are closed into a loop, same as Triangulate. Only applies while Profile Closed is on — an open profile is taken exactly as it comes. | int | 0 |
| Profile ClosedWhether the cross-section is a loop. On gives a solid tube; off sweeps an open ribbon, which is what you want for a strip, a road or a strap. | bool | true |
| Path ClosedWhether the spine loops back on itself. On joins the last ring to the first — a circle along a circle is a torus — and the residual twist a closed loop always accumulates is spread out so the seam meets. | bool | false |
| CapsFills both ends. Only possible with an open path and a closed profile: an open profile has no cross-section to fill, and a closed path has no ends to fill it at. | bool | true |
| Segment StartWhere along the spine the solid begins. On a closed spine, or an open one with Segment Wrap off, it is a plain fraction of the length; with Wrap on it is the position in a PASS across the path. Park it here and animate Segment Offset instead. | float | 0 |
| Segment LengthHow much of the spine to use, from Segment Start onward; 1 is all of it. The cut ends land exactly where you ask rather than snapping to the nearest point, so the window slides smoothly instead of stepping. Part of a closed spine is OPEN, so the piece caps: a quarter torus is a bent tube. | float | 1 |
| Segment OffsetAdded to Segment Start, and the port to animate. It counts LAPS and is unbounded: 0 to 1 is one circuit, 1 to 2 the next, so a rising ramp runs the piece round for ever. Several Sweeps on one spine with different Starts and the SAME Offset are carriages on a train: evenly spaced, one clock. | float | 0 |
| Segment WrapWhat happens at the ends of an OPEN spine. On, the window makes a full PASS: it grows in at the near end, travels whole, shrinks away at the far end, then begins again — one unit of Offset is one whole pass. Off, it stops at the end and stays whole. A closed spine has no ends and laps either way. | bool | true |
| TwistHow far the profile turns over the whole run, in degrees. A square profile twisted 90 degrees over a straight path is a classic twisted column. | float | 0 |
| Scale StartThe profile’s size at the beginning of the path. | float | 1 |
| Scale EndThe profile’s size at the end — lower than Scale Start tapers the sweep to a point, which turns a pipe into a horn or a spike. | float | 1 |
Outputs
| Port | Type |
|---|---|
| Geometry | structure |
| Vertex Count | int |
| Triangle Count | int |
How It Works
Sweep carries a profile along a path: a circle along a line is a pipe, a rectangle along a spiral is a ribbon, any outline along any curve is the general case. Both inputs are ordinary point clouds, so the profile can come from Path, Triangulate or a tracked outline, and the spine from Path, a hand or a particle trail.
The frame is parallel transported rather than derived from curvature, so a straight run does not spin and an inflection does not flip — the two failure modes of the naïve approach. A closed path has its residual twist spread out so that the seam meets.
Twist turns the profile along the way; Scale Start and Scale End taper it.
The segment window is the node's trick. Segment Start, Segment Length and Segment Offset take only part of the spine and slide that window along it: park it with Start, drive Offset from an LFO, and the piece rides the path. Offset counts laps and is unbounded — 0 to 1 is one circuit, 1 to 2 the next, for as long as you feed it. Several Sweeps on one spine with different Starts and a shared Offset are carriages on a train. On a closed path the window wraps round the seam, and taking part of a loop opens it, so the piece caps like any other open sweep.
Use Cases
- Pipes and tubes — A circle profile along any curve.
- Ribbons — A thin rectangle along a spiral or a helix.
- A train on a track — Several Sweeps with staggered Segment Starts and one shared Offset.
- Growth animation — Segment Length from 0 to 1 grows the object along its own spine.
- Trails as geometry — A particle path or a tracked hand's route as a real, lit, shadow-casting mesh.
Tips
- Resample both the profile and the spine to sensible counts — the mesh is profile × spine in size.
- Segment Offset is in laps, not units, so an LFO from 0 to 1 is exactly one circuit.
- Path Closed matters: it changes both the twist distribution and how Offset wraps.
- Scale Start and End are the cheapest way to make a pipe read as a horn or a tentacle.
- If the profile spins along a straight run, check that the spine really is a Path and not an unordered cloud.
Open Sweep in the interactive catalog →
Sweep is one of 381 nodes in Grafit Pro.
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