What to use as the cross-section shape. The default is to use curves connected to this node’s second input.

The surface topology of the generated surface.

The Columns option is useful for creating many curves from each input curve.

When Surface shape is “Second Input”, this uniformly scales the size of all cross-sections. For finer control, you can also use the scale ramp below to scale along the length of the curve, or a pscale or scale point attribute on the spine curve to scale the cross sections (when Transform Using Curve Point Attributes is on).

When Surface shape is “Round tube”, “Square tube”, or “Ribbon”, this controls the density of the cross-section shape. For round, this is the number of sides the circle has. For square, this is the number of subdivisions along each side. For ribbon, this is the number of subdivisions across.

When Surface shape is “Round tube”, the radius of the tube.

When Surface shape is “Square tube” or “Ribbon”, the width of the tube/ribbon.

Turn this on to reverse the normals of the generated surface.

When this is on, the node treats cross section primitives as if they were reversed, which reverses normals on the generated surface.

Stretch cross-sections in the direction of curvature around turns in the spine. (Default on.) This avoids the cross-section appearing squished in turns. This is usually what you want, unless you have set Surface type to “rows” or “columns”.

When Stretch Around Turns is on, the maximum amount that cross sections will be stretched. The default is 10 (maximum 10× stretch). This prevents the cross-section from scaling wildly if, for example, the spine curve doubles back on itself.

When the spine curve is open and the cross-section curves are closed, the generated surface is a tube. The node can automatically create end-caps on the open ends of the tube.

When End Cap Type is Grid, the number of rows in the end-cap surfaces.

When End Cap Type is Grid and this is on, the poles of end caps are made with triangles. When this is off (the default), the poles are made with quads with duplicate vertices.

When End Cap Type is Grid, this is the amount each end-cap “bulges out” from each end of the tube. Set this to 0 for no bulge, or to a negative number for an inward bulge.

When End Cap Type is Grid, and End cap scale is not 0, this controls the curvature of the bulge. 1 is convex circular, 0 is linear, and -1 is concave circular.

When this is on, the output geometry includes a group by this name, containing all end-cap geometry. This lets you treat the end-caps separately if necessary in down-stream nodes.

Scales the generated surface across the length of the spine curve according to the Scale ramp parameter.

When Apply scale along curve is on, this ramp lets you interactively scale the surface inward and outward along the length of the spine curve.

The order in which to apply the Pitch (around X/out), Yaw (around Y/up), and Roll or Twist (around Z/tangent) options below, when more than one can apply.

Pitch and Yaw may be useful to effectively apply a pre-transform to the cross sections before using them if they are not in the XY plane in the cross section input, which is why they default to being applied before the Roll or Twist.

These rotations are effectively applied to the cross sections before the transforms from the backbone curves, having the net effect of them being rotations in the space of the backbone curve frames.

Apply the Roll and Twist parameters below to the cross-section curves.

A rotation, in degrees, around the spine curve direction, applied equally to every cross-section. You can use this to correct the orientation of the cross-section in relation to the curve.

A convenience to add full twists (for each interval set in the Twist per parameter). This node multiplies this by 360 and adds it to the number in Partial twist.

The number of degrees of twist to add (for each interval set in the Twist per parameter).

The interval along each of which the total twist specified by the Full twists and Partial twist parameters is applied to the surface.

See the descriptions and image below.

When Twist Per is “Scale By Attribute”, this is the name of the vertex, point, primitive, or detail attribute to multiply by the total twist amount (full twists combined with partial twist). This product is applied as a roll at each vertex, not as an accumulating twist.

Apply the Yaw parameters below to the cross-section curves. Yaw is a rotation around the cross-section’s “up” vector, usually thought of as “turning left or right”.

A rotation, in degrees, around the cross-section’s “up” vector, applied equally to every cross-section. (This is usually thought of as “turning left or right”.) You can use this to correct the orientation of the cross-section relative to the curve.

A rotation, in degrees, around the cross-section’s “up” vector (usually thought as “turning left or right”), to apply along each interval set in the Yaw per parameter.

The interval along each of which the total rotation specified by the Incremental Yaw parameter is applied to the surface.

When Yaw Per is “Scale By Attribute”, this is the name of the vertex, point, primitive, or detail attribute to multiply by Incremental Yaw. This product is applied as a yaw at each vertex, not as an accumulating yaw.

Apply the Pitch parameters below to the cross-section curves. Pitch is a rotation around the cross-section’s “out” vector, usually thought of as “tilting up or down”.

A rotation, in degrees, around the cross-section’s “out” vector, applied equally to every cross-section. (This is usually thought of as “tilting up or down”.) You can use this to correct the orientation of the cross-section relative to the curve.

A rotation, in degrees, around the cross-section’s “out” vector (usually thought as “tilting up or down”), to apply along each interval set in the Yaw per parameter.

The interval along each of which the total rotation specified by the Incremental Pitch parameter is applied to the surface.

When Pitch Per is Scale By Attribute, this is the name of the vertex, point, primitive, or detail attribute to multiply by Incremental Pitch. This product is applied as a pitch at each vertex, not as an accumulating pitch.

How the node decides what cross section(s) to use a each point along the spine curve.

When Cross Section Order is “Choose Cross Section Primitives by Attribute”, this is the name of the attribute to use for selecting cross sections.

This can be a point, vertex, primitive, or detail attribute on the spine curve, or a primitive attribute on the cross-sections.

• If this is an integer attribute on the spine, it will select cross sections by primitive number.

• If this is an integer or string attribute present on both inputs, it will select a cross section with a matching value.

The type of primitive to output (when Surface Type is not “Points”). “Automatic” generates the same type of surface as the input curves (for example, polylines create a polygon surface, NURBS curves produce a NURBS surface).

If Surface Type is “Rows”, “Columns”, or “Rows and Columns”, and the spine curve or cross-section is closed, this adds an extra vertex (if needed) to each curve to ensure that there are separate vertices for parametric curve u or v coordinate values 0 and 1.

If any output primitives are polygon soups, NURBS surfaces, Bezier surfaces, or bilinear mesh primitives, this option similarly also adds any extra vertices that would be needed to ensure that all uv seams are paramerized correctly.

Adjusts the order of the points and primitives in the generated surface(s) to be column-major, having all points/primitives of one column before those of the next column, instead of the default (row-major, having all point/primitives of one row before those of the next row). Changing this also reverses normals, so you may also want to turn on Reverse Cross Sections to keep the current normals.

If the node finds no spine curve in the first input, the node sweeps the cross sections in the second input as if there is a single curve with one vertex per cross section and all positions at the origin. When this is on, the node makes that implicit curve closed, treating the cross sections as forming a loop, instead of a line.

The initial orientation of the cross-section around the direction of the curve. You can use the roll, yaw, and pitch parameters on the Surface tab to further adjust the orientation of the cross-sections on top of this.

When this is on, at each point the node tries to get closest to the initial up-vector, while staying perpendicular to the spine curve tangent. When this is off, it tries to get closest to the average of all vertex up-vectors, instead of the initial up-vector.

When Target up-vector at Start is on, and this is on, the node adjusts any twist along the spine to ensure the final up-vector is as close as possible to the target up-vector, without affecting the initial up-vector.

If Target up-vector is “Attribute” or “Custom”, there are separate End Up Attribute and End Up Vector parameters, in order to specify different end up-vectors from the start up-vectors.

When Target Up Vector is Attribute, this is the name of the primitive or detail attribute to use for each curve’s target up-vector.

When Target Up Vector is Attribute and Use Target End Up Vector is on, this is the name of the primitive or detail attribute that provides the target up-vectors at the end of the curve.

When Target up-vector is “Custom”, this is the target up-vector at the end of the curve.

When Target up-vector is “Custom” and Use Target End Up Vector is on, this is the target up-vector at the end of the curve.

How to compute the spine curve’s tangent direction at each point. If Transform using curve point attributes is on and the spine curve has the required attributes, this is ignored.

(The Stretch Around Turns option always computes the stretch and stretch direction based on the “Average of Edge Directions” tangent, regardless of this setting.)

Any extra rotation required to make the start and end orientations match (either because the curve is non-planar, or you applied a total amount of twist that wasn’t an even multiple of 360) is spread out along the entire curve, instead of possibly coming suddenly along the last edge.

Extrapolate the tangent for the last edge from the previous two edges. When this is off, the tangent for the final edge is just the edge direction.

This is most useful when a backbone curve is intended to represent a circular arc, so the end cross sections will be rotated as expected.

You can also scale the cross-section using pscale or scale point attributes on the spine curve, and orient the cross-sections using the point attributes P, N, up, orient, rot, trans, pivot, and/or transform on the spine curve.

• If N is present and none of up, orient, rot, or transform are present, the node uses N as the curve tangent and computes the rest of the rotation as usual.

• If up is present and none of N, orient, rot, or transform are present, the node computes the tangent as usual, and uses up as the up-vector at each vertex (before any roll or twist is applied).

Generate a uv vertex attribute on the generated surface. If the input curves already have uv attributes, the node uses the values from those attributes (U corresponds to the cross sections, and V corresponds to the spine curve).

(If Surface Type is “Points”, this will generate a point attribute.)

When Compute UVs is on, compute new UVs for the surface, even if the input curves already had uv attributes.

Scale the U and V coordinates based on proportional edge lengths so they're even across the whole surface, rather than bunching up where edges bunch up.

(If Normalize Computed Us and/or Normalize Computed Vs are on, the coordinates are still normalized to be within the 0 to 1 range.)

Normalize computed U coordinates to be in the range 0 to 1 (before applying UV scale). When this is off, U corresponds to the average distance around the cross sections on the mesh (ignoring any stretch applied by Stretch Around Turns).

When this is on and Normalize Computed Vs is off, the node scales V such that U and V appear scaled similarly in space (depending on the Use Max Cross Section Length per Curve for Proportional Scale setting).

This is especially useful for things like applying repeating rope textures, where the texture should be applied isotropically.

Normalize computed V coordinates to be in the range 0 to 1 (before applying UV scale). When this is off, V corresponds to the average distance along the surface in V, or the distance along the spine curve, depending on the Use Mesh Edge Lengths instead of Curve Edge Lengths parameter.

When this is on and Normalize Computed Us is off, the node scales U such that U and V appear scaled similarly in space.

Reverse the direction of the computed U values (same as replacing each U value with max(U values) - U). Use this if a texture appears backward when applied to the surface.

This should be on for textures to appear correct on surfaces viewed from the front, (normals pointing toward the camera), and should be off for textures to appear correct on surfaces viewed from the back, (normals pointing away from the camera).

A scale on the generated UV coordinates. This is applied after any normalization.

This is applied before the adjustments made by Make Computed Us Wrap Seamlessly and/or Make Computed Vs Wrap Seamlessly, so the texture will still wrap correctly.

When this is on and Length-Weighted UVs is on, the averages of the output mesh edge lengths in the curve direction are used as the lengths in the V direction, instead of the original curve edge lengths.

• This is useful when, for example, a curve has coincident points with different cross sections, such as a door jamb in a hallway, so that the surface between the two cross sections gets a non-zero area of texture space.

• It is also useful for generating UVs for grid end caps. However, it can be less stable, when changing rotations, than using the original curve lengths.

When Normalize Computed Us is on and Normalize Computed Vs is on, this controls whether the node uses the maximum cross section length for computing the V scale, instead of the average of the previous and next cross section lengths for each V edge.

If the cross section length varies significantly, this can make the texture appear stretched in some places, but can also avoid instability and inconsistency in the V scale along the curve.

When Normalize Computed Us is off and this is on, the node rounds the range of U to the nearest positive integer, so textures wrap correctly in the U direction. This node applies this rounding after the UV Scale.

When Normalize Computed Vs is off and this is on, the node rounds the range of V to the nearest positive integer, so textures wrap correctly in the V direction. This node applies this rounding after the UV Scale.

Space-separated list of attributes to copy from the backbone curve onto the generated surface. You can use patterns here.

By default, P, N, up, pscale, scale, orient, rot, pivot, trans, and transform are not copied, to avoid copying attributes used for computing transforms.

Space-separated list of attributes to copy from the cross-section curves onto the generated surface. You can use patterns here.

The transforms attributes that have a transform type (position, vector, normal, quaternion, or transform matrix) appropriately.

Create an integer point attribute with this name on the generated surface, containing the row number.

Create an integer point attribute with this name on the generated surface, containing the column number.

Create an integer point attribute with this name on the generated surface, containing the quad row number.

Create an integer point attribute with this name on the generated surface, containing the quad column number.

Create an integer point attribute with this name on the generated surface, containing the primitive number of the cross section curve used to create the point.

Create an integer point attribute with this name on the generated surface, containing the primitive number of the spine curve used to create the point.