Overview#
Sweep slides a 2D profile along a 3D path to create a solid (or surface). Typical uses are handles, cable channels, trim, picture frames, gutters, handrails, hoses, and any shape with constant (or evenly varying) cross-section that follows a curve.
A sweep needs at least:
- a profile (a sketch profile or planar face; Autodesk's Solid Sweep type instead sweeps a solid body), and
- a path to sweep along.
For more control you can add a guide rail or guide surface that controls the scale and orientation of the swept geometry.
If the cross-section is constant and circular, the Pipe tool is faster. If the profile must change shape along the way, use Loft.
Where to find it#
- Workspace: Design.
- Tab / panel: Solid tab > Create > Sweep.
- Shortcut: none listed in Autodesk's shortcut reference; press S and type "Sweep".
- Surface tab: Surface > Create > Sweep makes surface sweeps from open profiles.
Step by step#
- Create the path first. Sketch on a plane, for example an L-shape with a tangent arc corner on the XY plane. Finish the sketch. For 3D paths, use a 3D sketch or the Spline tool in 3D sketch mode, or select model edges.
- Create the profile sketch. The profile plane should be roughly perpendicular to the path at its start. Use Construct > Plane Along Path to place a plane exactly normal to the path at a chosen distance (see the Construction Geometry page).
- Draw the profile. For a handrail, draw a rounded rectangle centered at the path's start point. Use Project to tie the profile to the path endpoint, or add a Coincident constraint between the profile center and the path end.
- Finish the sketch and open Create > Sweep.
- Pick Profile, then Path. If the path has multiple connected segments, leave Chain Selection on so tangent-connected curves are picked together.
- Choose Type: Single Path, Path + Guide Rail, Path + Guide Surface, or Solid Sweep.
- Set Orientation (Perpendicular or Parallel) and optional Distance, Taper Angle and Twist Angle.
- Pick the Operation and confirm.
Worked example: a coat hook#
- On the XZ plane draw a path: a vertical line 20 mm, tangent arc radius 30 mm, then a 25 mm line.
- Create Plane Along Path at distance 0 on the path's start.
- Sketch a 12 mm circle centered at the path start on that plane.
- Sweep: profile = circle, path = chained curves. Operation New Body.
You get a hook with a smooth bend. If the arc looks kinked, the path lines are not tangent to the arc; fix with Tangent constraints.
Options reference#
| Option | What it does | Notes/default |
|---|---|---|
| Type: Single Path | Profile follows one path. | Default. |
| Type: Path + Guide Rail | The guide rail controls the scale and orientation of the swept geometry. | Adds Guide Rail and Profile Scaling options. |
| Type: Path + Guide Surface | The guide surface controls the scale and orientation of the swept geometry. | Useful for trim that follows a curved panel. |
| Type: Solid Sweep | Sweeps a selected solid body along the path. | Selector is Body instead of Profile; Orientation gains Aligned (orients the object to a selected axis, and it may rotate around that axis). |
| Profile | A profile or planar face. | |
| Path | The path to sweep along. | Use Chain Selection for connected segments. |
| Guide Rail | A curve that controls profile scale and orientation. | Rail types only. |
| Profile Scaling | Scale: uses the path-to-rail distance to scale the profile in X and Y. Stretch: scales in X only, keeping height. None: the rail only guides orientation. | Rail types. |
| Extent | Perpendicular To Path or Full Extents. | Listed in the reference; behavior details not documented there. |
| Distance | Fraction of the path swept, from 0.00 to 1.00 (Autodesk's reference). | Lets you sweep just part of a long path. |
| Taper Angle | Tapers the sweep by the angle you specify. | Flip the sign to reverse shrink/grow. |
| Twist Angle | Twists the object around the path. | Used for twisted ribbons. |
| Orientation: Perpendicular | Orients the swept body perpendicular to the path. | |
| Orientation: Parallel | Orients the swept body parallel to the path. | A sensible choice for straight-sided shapes on curved paths; preview it. |
| Chain Selection | Automatically selects tangentially connected geometry. | Turn off to pick individual edges. |
| Analysis tab | Zebra, Curvature Map or Isocurve analysis of the previewed result. | Select Bodies to analyze. |
| Objects To Cut | Cut/Intersect only: Auto-Select recomputes bodies from visibility; "# Bodies" keeps the original ones. | Only active when editing. |
| Operation | Join, Cut, Intersect, New Body, New Component. | New Component is Hybrid design only. |
Tips and pitfalls#
Tip: Place the profile sketch on a plane created with Plane Along Path so the profile is exactly perpendicular to the path. Misaligned planes cause lopsided sweeps.
Tip: Use a sweep Cut to carve channels around parts, such as an O-ring seat that follows a non-circular perimeter.
Warning: If the path has a sharp corner (non-tangent), a sweep with Perpendicular orientation may fail or produce a twisted mess. Add a fillet in the path sketch with a radius larger than half the profile width.
Warning: Sweeping a profile whose size exceeds the path's smallest bend radius will self-intersect. Reduce the profile or increase the bend radius.
- The profile does not have to touch the path. Fusion keeps the offset between them, which is useful for rails offset from the path (such as a rib offset from a reference curve).
- Projecting model edges into the path sketch is better than selecting body edges directly if you want the sweep to survive model edits; selected edges do work, but edits that change the topology (splitting edges) can break references.
- A 3D path (for example a spline in a 3D sketch) can be used. For helices, prefer Coil.
- Use Twist Angle with a rectangular profile to create a twisted bar. A Twist of 360 degrees is one full turn.
- To sweep along an open path with an end cap flush to a surface, extend the path slightly past the surface and use Intersect or Cut afterward.
- As general practice, keep guide rails touching the profile plane; constrain the rail start to a profile vertex or its plane.
Planning a sweep#
Path quality. A path with tangent-continuous segments (lines tied to arcs with Tangent constraints) gives clean sweeps. A path with a sharp corner makes the profile jump. Make bends at least as large as the profile half-width plus a margin: a 12 mm round profile needs path radii above 6 mm, and practically above 12 mm to avoid a pinched inner surface.
Profile placement. The profile does not have to be perpendicular to the path in the sketch, but if it is not, Perpendicular orientation reorients it at the start and the result may differ from your drawing. Plane Along Path (Distance 0) gives an exactly perpendicular profile plane.
Orientation, taper and twist with numbers#
- Perpendicular keeps the profile normal to the path tangent all the way. On a 90 degree bend, the profile rotates 90 degrees along with it.
- Parallel orients the swept body parallel to the path. A rectangle swept along a curved path with Parallel keeps its sides parallel to their original direction, which can suit a straight-sided bar running over a curved top; preview it to confirm.
- Taper Angle tapers the sweep. As an approximation, a 20 mm square swept 100 mm with a 1 degree taper shrinks by about 2 x 100 x tan(1) = 3.5 mm in total width at the far end.
- Twist Angle is the total rotation over the swept length. A 360 degree twist on a 100 mm sweep of a rectangular bar turns it once; 90 degrees turns it a quarter. Test with 90 degrees first and increase from there.
- Distance 0.5 sweeps only half of the path. Use it to build a feature in two stages with different profiles.
Guide rails#
Path + Guide Rail uses the rail to control the scale and orientation of the swept geometry; Profile Scaling (Scale, Stretch or None) sets how. Use it for a tapered handle where the outline is a spline: draw the path as the centerline and the rail along the outer silhouette. As general modeling practice, keep the rail touching the profile plane (constrain a rail endpoint to a profile vertex) to avoid failures.
Path + Guide Surface uses a surface to control scale and orientation, for example trim that follows a curved panel.
Sweep as Cut#
A Cut sweep carves channels. For an O-ring seat that follows a stadium-shaped perimeter, draw the perimeter as the path and the groove's rectangle as the profile at the path start, then Sweep with Operation Cut. As general guidance (not Autodesk data), a 3 mm O-ring cord in a static face seal needs a groove roughly 2.4 mm deep and 3.8 mm wide; confirm with the O-ring supplier's gland table. If the path lies on the face of the body, the groove depth must be reflected in the profile, not in the path.
Worked example: a handrail with a guide#
- Path: a 400 mm line, then a tangent arc of radius 150 mm turning 90 degrees, then a 300 mm line, all in one sketch.
- Plane Along Path at Distance 0. Sketch a 40 x 30 mm stadium (slot) profile centered on the path start.
- Sweep with Chain Selection on, Perpendicular. The 150 mm bend radius far exceeds the 15 mm profile half-height, so no pinching.
- Reduce the bend radius to 10 mm and observe the failure, then restore.
- Set Taper Angle to 0.5 degrees and check the end width. Depending on sign it grows or shrinks by about 2 x 850 x tan(0.5 degrees) = 14.8 mm over the 850 mm path; flip the sign to reverse it.
Failure modes and fixes#
| Symptom | Cause | Fix |
|---|---|---|
| Sweep fails on a corner | Sharp corner in the path | Add a path fillet larger than half the profile |
| Profile twists unexpectedly | Profile sketched off-perpendicular | Use Plane Along Path for the profile sketch |
| Sweep self-intersects inside a bend | Bend radius smaller than the profile | Increase the radius or reduce the profile |
| Rail sweep fails | Rail does not touch the profile plane | Constrain the rail to the profile |
| Result stops partway | Distance below 1.0 | Set Distance to 1.00 |
| Cut sweep removes from other bodies | Overlapping visible bodies | Hide bodies before cutting, or edit and use Objects To Cut |
| Chain selects too much or too little | Chain Selection on with branching edges | Turn it off and pick segments |
Practice exercise#
Make three sweeps that each demonstrate a different control.
- Picture-frame molding: draw a 100 x 80 mm rectangle on XY as the path with 2 mm corner radii (try without radii first and record the result). Create a Plane Along Path at the start and sketch an L profile 10 mm by 15 mm with a 3 mm rabbet. Sweep with Perpendicular orientation. Confirm each corner is smooth. Compute the mitered length of the outer edge.
- Twisted bar: sweep a 10 x 5 mm rectangle along a straight 100 mm line with Twist Angle 90 degrees, then 180 degrees, then 360 degrees. Compare the results and report whether any value fails.
- Tapered handle: a 150 mm path curved in the XZ plane, a 20 mm circle profile, and a guide rail that narrows to 10 mm at the end. Compare it with a single-path sweep using a Taper Angle of about 1 degree, which shrinks the diameter by about 2 x 150 x tan(1 degree) = 5.2 mm, so the end is 14.8 mm.
- Cut: sweep a 3.8 x 2.4 mm rectangle along a 40 x 30 mm rounded rectangle path on a block face to make an O-ring groove.
Expected result: a smooth frame, a set of twisted bars with the failure point recorded, a tapered handle built two ways, and a groove. Write down which orientation you used for each and why.
Related#
- Loft (varying sections)
- Coil and Pipe (spiral and constant round sections)
- Construction geometry (Plane Along Path)
- Extrude and Revolve (simpler path types)