History enabled.

Crease splitting enabled.

The ExtrudeCrvAlongCrv command creates a surface by tracing the path of a curve along another path curve.


1. Select a curve.
2. Select the path curve.


If the curve is not planar, then it will be extruded in the z-direction of the active viewport's construction plane. If the curve is planar, it will be extruded in the normal direction of the plane of the curve.
Unlike Lofts and Sweeps, the initial orientation of the profile curve or surface is maintained through the extrusion.
If the input is a non-planar polycurve or a planar polycurve where the extrusion direction is not normal to the curve plane, the result will be a polysurface rather than an extrusion object.

Command-line options


If the profile curve is closed and planar, both ends of the extruded object are filled with planar surfaces and joined to make a closed polysurface.



Deletes the original geometry.


Retains the original geometry.


The SubCurve option extrudes a curve the distance specified by picking two points along a curve.

Note: The extruded surface starts from the beginning of the curve, not the first picked point. Picking the points only establishes the extrusion distance.

Subcurve steps

1. Select the path curve.
2. Pick a start along the path curve.
3. Pick an end along the path curve.


The Yes option creates a single surface.

The No option creates a polysurface when the input curves are joined tangent curves. Faces in the resulting polysurface correspond to the tangent sub-curves in the input curves.

Original polycurve (left), SplitAtTangents=No (center), SplitAtTangents=Yes (right).


When this option is used, the output will be a polysurface.
When UseExtrusions is on, this setting has no effect.

See also

Extrude curves and surfaces

Rhinoceros 5 © 2010-2015 Robert McNeel & Associates. 17-Sep-2015