Houdini 20.0 Nodes Geometry nodes

Wire Deform geometry node

Deforms geometry captured to a curve via the Wire Capture node.

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Parameters

Group

Optional point group to limit the points which are deformed. If empty, all points are deformed.

Rest Group

Specifies the primitive groups to used for deforming from the second input. This is currently only used for the Initialize From Rest Groups parameter button.

Parameters

Blending

Specifies the method used for blending displacements for points which are affected by more than one primitive. The current options are:

Max Displace

The individual displacements are added together and the length of the result is clamped to the maximum of the individual ones.

Biased Displace

The result is a normalized weighted average using the individual displacement lengths raised to the exponent specified in the Tension parameter.

Weighted

The result is normalized weighted average of the individual displacements according to their weight value assigned by WireCapture. Each weight is raised to the exponent specified by the Tension parameter.

Tension

If the Blending parameter is Biased Displace or Weighted, then this specifies the exponent used. The larger the value, the greater the bias will be towards the larger weight values giving a higher “tension”.

Transform Local Frame

Controls the rotation of the local frames on the curve (wire). Rotating a local frame causes the deformed point on a geometry to rotate around the curve point that captured it. Aligning local frame on the curve makes the deformed points follow the curve more closely. The current options are:

No Transform

The local frames on the curve will not be aligned with the local frames of the deforming curve. The deformed geometry will be only translated.

Align Tangent

Only the tangent vector of the rest frame will be aligned with the local tangent of the deforming curve. This option will rotate the deformed geometry so that any vector on a rest geometry that was parallel to the capturing tangent of the curve will appear to be parallel to the tangent of the deforming curve.

Align Tangent And Attrib Normal

If a normal attribute is specified for the deforming curve then the deformed geometry is rotated so that any vector that was parallel to the normal in the rest arrangement will be also parallel in the deformed space.

Treat Polygons As Lines

This specifies the behavior used for closed polygon primitives when told to shift points along primitives in the U Deform parameter. If on, then the tangents shoot off at first and last vertices of the closed polygon primitive. If off, then the tangent of the last vertex will shoot off from right before it wraps to the first vertex. The value of this parameter should be the same as the one specified in the WireCapture SOP used.

Recompute Point Normals

If enabled, this will recompute the point normals after deformation.

Assume Only Coordinate Changes In Input

Enables the assumption that only point positions need to be re-cached when the input geometry has changed to allow faster cooking. Unpredictable results will occur with this enabled if attributes or topology changes.

Visualize Weighting

If on, this will generate point color attributes reflecting the wire capture weights.

Visualize Type

This specifies the type of visualization used when Visualize Weighting is turned on.

Single Primitive

Shows the weight of each primitive along a color gradient. For points affected by multiple primitives, it will use the blended deformation weight for coloring.

Multiple Primitives

Uses a blend of primitive colors found in the second input. If they don’t exist, then Single Primitive is used.

Visualize Mode

This specifies the gradient used for visualization.

Infra-red

Utilizes the entire color spectrum where they range from blue (0) to red (1).

White to Red

Provides a gradient which varies from white (0) to red (1).

Grayscale

Provides a gradient which ranges from black (0) to white (1).

Blackbody

Ranges from black (0) to red, yellow, then white (1).

Zero Weight Point Color

This specifies the color used for points which are not affected by any capture primitives when using the Multiple Primitive visualize type.

Deform

Initialize From Rest Primitives

This will initialize the parameters below using the primitives found in the second input. An entry is created for each primitive using it’s primitive number.

Initialize From Rest Groups

This will initialize the parameters below using the primitive groups found in the second input. An entry is created for each named primitive group.

Number of Deformers

This specifies the number of deformer parameter sets that we wish deform. Each set below has a toggle to indicate whether it should be active.

Primitive

This specifies the primitive group for which the Scale, U Deform, and Clamp to Ends parameters apply.

Scale

The specifies a radial scale around the deforming primitive to apply.

U Deform

This specifies a parametric u range to deform the points along their capturing primitives. The first component specifies the new start u value and the second component gives the new end u value. The start value must be less than or equal to the end value. These values are relative to the U Range values of their corresponding primitive specified in the WireCapture SOP. For example, if the point was captured to a primitive using the u range of [0.3,0.7], then the U Deform parameters will map a value of 0 to 0.3 and a value of 1 to 0.7.

Clamp to Ends

If on, then when the U Deform parameters cause points to be extended beyond the length of the deforming primitive, they will be clamped to the maximum/minimum u values. If off, then the points are allowed to extend off the primitive using the tangents at the end points.

Inputs

First

Input geometry to deform. Must be first captured using WireCapture.

Second

Rest primitives. Must match third input in terms of number of primitives and their order. This should be the same as the second input into the WireCapture SOP. If it is desired that the points be deformed long a different path, then they may be modified from the second input of the WireCapture.

Third

Deforming primitives. Must match second input in terms of number of primitives. This is typically a Edit SOP branched off from the sop piped in the second input.

Examples

TwistWireDeform Example for Wire Deform geometry node

This example demonstrates how to define local coordinate frames for use with the Wire Deform SOP.

See also

Geometry nodes