Surface Creation
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Extrude Curve > Ribbon

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The Ribbon command Offsets a curve and creates a ruled surface between the two curves.


  1. Select a curve.
  2. Drag the cursor to one side of the curve and pick.

Command-line options


Sets the offset distance.


The Corner and Tolerance options are not shown and do not affect the output. Polycurves are offset as a group of separate curve segments, and there is no corner trimming or filling.


Specifies how corners are handled when they are offset to the "convex" side as pointed out in the image.

Original curve (blue). Offset to outside (red). Offset to inside (green).

Curves offset to the outside of a corner will be extended to meet at sharp corners with position (G0) continuity.


Curves offset to the outside of a corner will be filled with arc segments with tangent (G1) continuity.


Curves offset to the outside of a corner will be filled with blend segments with curvature (G2) continuity.


The corners of the offset curves will be filled with a straight line between their endpoints.


Offsets through a picked point instead of at a distance.


Sets the tolerance for the offset curve. Type 0 to use the default system tolerance.


Offsets the curve on both sides of the input curve.


The curve is offset in the plane of the original curve. This option offsets the curve in the plane of the current construction plane instead.


Place the results on the current layer.


Place the results on the same layer as the input objects.




Curve Tools

Surface Creation


Offset > Ribbon Offset

The RibbonOffset command offsets a closed curve and then creates a ruled or sweep2 surface between the input and offset curves.

Offset curve options

Offset distance

The distance between the input and offset curves.

Blend radius

Controls the approximate radius of the blend curve used to trim the intersected corner between two offset curve segments.

Do not change offset curve

Uses the original offset curve to create the ribbon surface.

Rebuild offset curve with ___ control points

Uses the specified control points count to rebuild the offset curve.

Refit offset curve within ___ (System unit)

Uses the specified tolerance to refit the offset curve.

Ribbon surface options

Surface creation method

Creates the offset curve but not the ribbon surface.

Sweep 2

Creates the ribbon surface using Sweep2 only.

Add Slash

Manually adds sections to reduce twisting along the sweep.

Mixed Sweep2 / NetworkSrf

Creates the ribbon surface as the Sweep 2 method, but uses NetworkSrf on the corners where the offset segments do not intersect.

Align cross sections

Places cross-sections near the mid points of the rail segments and creates the ribbon surface using Sweep2.


Displays the ribbon surface before it is created.

Additional output options

These curves are always created from the ruled ribbon surface, the one created by the Mixed Sweep2 / NetworkSrf method.

Output cross sections

Duplicates cross-section edges of the ribbon surface as lines.

Output curve segments

Duplicates the edges of the ribbon surface rails as separate curve segments.

See also

Extrude curves and surfaces





Rhinoceros 8 © 2010-2024 Robert McNeel & Associates. 07-Jun-2024