The overall method for computing tangents at each vertex. If Transform Using Point Attributes is on and the input has point N (vector), orient (quaternion), rot (quaternion), or transform (3×3 or 4×4 matrix), this is ignored in favor of the Z axis from the transform determined by these attributes. The Stretch Around Turns option always computes the stretch and stretch direction based on the Average of Edge Directions tangent, regardless of this tangent type, since it’s undefined otherwise. See the descriptions and image of the options below.

When enabled, any accumulated roll (torsion) around a closed curve will be canceled out in a manner spread out around the curve, instead of suddenly in the final edge. Planar curves don’t have any inherent accumulated roll around the curve, but this applies to the Partial Twist option (when Apply Roll or Twist is enabled) as well, so any twist that isn’t a multiple of a full twist will be rounded to a multiple of a full twist.

When enabled, end (including beginning) tangents will be extrapolated based on the Tangent Type and the two edges closest to the end, instead of just being chosen as the end edge direction. This is most useful for cases similar to when a curve is intended to represent a circular arc, so that end orientations will be rotated as expected. See the image above.

When enabled, any point attributes P, N, up, orient, rot, trans, pivot, pscale, scale, and transform will be used to form each transform, primarily as specified here. If N is present and none of up, orient, rot, or transform are present, N will be used as the curve tangent and the rest of the rotation will be computed as usual. If up is present and none of N, orient, rot, or transform are present, the tangent will be computed as usual, and up will be used as the up vector at each vertex, before any Apply Roll or Twist is applied.

Up vector for each curve to target, to break the tie between all possible rolls around the tangent. If a curve is planar, the Curve Normal option should ensure that the up vector is perpendicular to the plane; if the curve is a straight line, this option will fall back to using the y axis as a target up vector. The Attribute option can use a primitive or detail attribute to select the up vector for each curve. To specify separate up vectors on all curve points, use the Transform Using Point Attributes and provide a point attribute named up, in which case, this target up vector is ignored.

When enabled, the roll for each curve is chosen such that the up vector of the first vertex is as close as possible to the target up vector while still being perpendicular to the tangent vector. When disabled, that applies to the average of all vertex up vectors, instead of the first vertex. This must be enabled in order to use the Use Target End Up Vector Option.

When enabled and Target Up Vector at Start is enabled, the twist along each curve is adjusted to ensure that the end up vector is as close as possible to the target up vector, without affecting the start 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 at Start is enabled, this provides the target up vectors at the start of the curves. When Target Up Vector at Start is disabled, this provides the target for the average up vector along each curve.

When Target Up Vector is Attribute and Use Target End Up Vector is enabled, this is the name of the primitive or detail attribute that provides the target up vectors at the end of the curves. The twist of each curve is adjusted to ensure that the end up vector is as close as possible to the target end up vector, without affecting the start up vector.

When Target Up Vector is Custom, this is the target up vector to use for each curve. When Target Up Vector at Start is enabled, this provides the target up vector at the start of the curves. When Target Up Vector at Start is disabled, this provides the target for the average up vector along each curve.

When Target Up Vector is Custom, this is the target end up vector to use for each curve. The twist of each curve is adjusted to ensure that the end up vector is as close as possible to the target end up vector, without affecting the start up vector.

When enabled, up vectors are adjusted towards the center of curvature. Using the computed tangents and how they change from point to point, curvature vectors are computed and then scaled by the Curvature Scale. Up vectors are then recomputed as the normalized sum of the up vector and the perpendicular component of the scaled curvature vector.

If the up vectors and curvature vectors are close to pointing in opposite directions, the up vectors may be seen to flip suddenly where the curvature vectors become greater in magnitude than the up vectors. For the best results, the angle between up vectors and curvature vectors should not be close to 180 degrees.

Scales curvature vectors by a uniform amount. Applies to both computed curvature vectors and those specified in an attribute by the Curvature Attribute.

When enabled, scales the curvature vectors by an attribute on the curve points.

An attribute on the curve points to scale the curvature vectors by. This has a similar effect to introducing a speed at each point, and can be used to control how much the curvature influences the up vectors at each point.

When enabled, uses an attribute to specify the curvature vectors.

An attribute on the curve points used to specify the curvature vectors.

The order in which to apply the Pitch (around X/out), Yaw (around Y/up), and Roll or Twist (around Z/tangent) options below if multiple are enabled. Pitch and Yaw may be useful to effectively apply a pre-transform to whatever the orientation will be applied to, which is why they default to being applied before the Roll or Twist. These rotations are effectively applied before the transforms from the curves, having the net effect of them being rotations in the space of the curve frames.

When enabled, the parameters below for applying a roll rotation around the tangents (computed above) are enabled.

Rotation in degrees around the tangent, applied to every orientation, if Apply Roll or Twist is enabled.

Manner in which to apply the twist value specified below by (360*(Full Twists) + (Partial Twist)). See the descriptions and image below.

Integer number of full twists to add for each unit determined by Twist Per. This is just provided for convenience; it is just multiplied by 360 and then added to Partial Twist. If Twist Per is Per Full Curve by Edges or Per Full Curve by Distance, this corresponds with full twists along each full curve.

Twist in degrees around the tangent, to add for each unit determined by Twist Per. This is added to 360 times Full Twists.

When Twist Per is Scale By Attribute, this is the name of the vertex, point, primitive, or detail attribute to multiply by the combination of Full Twists and Partial Twist in degrees. This product is applied as a roll at each vertex, not as an accumulating twist, so that if the attribute goes from 0 to 1 along a curve, the twist value will be the total twist applied.

When enabled, the parameters below for applying a yaw rotation around the up vectors (computed above) are enabled.

Rotation in degrees around the up vector, applied to every orientation, if Apply Yaw is enabled.

Manner in which to apply the Incremental Yaw value specified below.

Yaw in degrees around the up vectors, to add for each unit determined by Yaw Per.

When Yaw Per is Scale By Attribute, this is the name of the vertex, point, primitive, or detail attribute to multiply by Incremental Yaw in degrees. This product is applied as a yaw at each vertex, not as an accumulating yaw, so that if the attribute goes from 0 to 1 along a curve, the Incremental Yaw value will be the total yaw applied.

When enabled, the parameters below for applying a pitch rotation around the out vectors (perpendicular to the tangent and up vectors computed above) are enabled.

Rotation in degrees around the out vector (perpendicular to the tangent and up vectors), applied to every orientation, if Apply Pitch is enabled.

Manner in which to apply the Incremental Pitch value specified below.

Pitch in degrees around the up vectors, to add for each unit determined by Pitch Per.

When Pitch Per is Scale By Attribute, this is the name of the vertex, point, primitive, or detail attribute to multiply by Incremental Pitch in degrees. This product is applied as a yaw at each vertex, not as an accumulating yaw, so that if the attribute goes from 0 to 1 along a curve, the Incremental Pitch value will be the total yaw applied.

When enabled, any scales or shears coming from Transform Using Point Attributes, for example from pscale, scale, or transform attributes, will be canceled out.

This scale is applied to the transform after Normalize Scales.

When enabled, this stretches the transforms in the direction of curvature around turns in the curves, which is primarily for use with cross sections, for example with the Sweep node to avoid the cross section appearing to be squashed along edges. This is usually the desired behavior in the Sweep node, but not usually for other uses.

When Stretch Around Turns is enabled, this is the maximum amount that transforms will be stretched, to avoid stretching too far when a curve almost reverses direction in a single turn.

Whether to create the output attributes on the points or the vertices. Transforms are always computed for vertices first. If output attributes will be point attributes and there are shared points, the separate transforms of the vertices will be averaged by separately averaging the rotations as quaternions, the translations, and any scales and shears.

When enabled, a vector attribute with this name will be created on the output that is perpendicular to the curve tangents (z axis) and up vectors (y axis). If a curve is planar and Target Up Vector is set to Curve Normal, this corresponds with the outward direction. If the attribute is named N, it will be marked as transforming like a normal, instead of a vector. If the input P attribute is 64-bit, this attribute will be 64-bit.

When enabled, a vector attribute with this name will be created on the output that corresponds with the up vector, perpendicular to the curve tangents (z axis). If the attribute is named N, it will be marked as transforming like a normal, instead of a vector. If the input P attribute is 64-bit, this attribute will be 64-bit.

When enabled, a vector attribute with this name will be created on the output that corresponds with the curve tangents. If the attribute is named N, it will be marked as transforming like a normal, instead of a vector. If the input P attribute is 64-bit, this attribute will be 64-bit.

When enabled, a position attribute with this name will be created on the output that corresponds with the translation coming from P, pivot, trans, and transform attributes when Transform Using Point Attributes is enabled, or just P when it is disabled. If the input P attribute is 64-bit, this attribute will be 64-bit.

When enabled, a quaternion attribute with this name will be created on the output that corresponds with the orientations along the curves. If the input P attribute is 64-bit, this attribute will be 64-bit.

When enabled, a 3×3 transform matrix attribute with this name will be created on the output that corresponds with the orientations along the curves, scales, and shears. If the input P attribute is 64-bit, this attribute will be 64-bit.

When enabled, a 4×4 transform matrix attribute with this name will be created on the output that corresponds with the orientations along the curves, scales, shears, and translations. If the input P attribute is 64-bit, this attribute will be 64-bit.