Houdini 20.0 Nodes Geometry nodes

Attribute Transfer geometry node

Transfers vertex, point, primitive, and/or detail attributes between two models.

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Attribute transfer works by proximity. It transfers attributes from one piece of geometry to the closest points on a different piece of geometry, so you can copy the attributes from one model to another even if they have completely different topologies.

Note

If you want to copy attributes between models with the same topology, use Attribute Copy, because it is much faster.

If you want to copy attributes between geometry in the same stream, use Attribute Promote (it has one input). If you want to copy attributes from geometry in one input onto geometry in another input, use Attribute Transfer.

Tip

If you wire the same geometry into both inputs of this node, you can use this node to “blur” attributes across surfaces.

Destination attributes are interpolated from the source attributes using a weighted proximity technique:

Attributes can be explicitly specified in the attribute text fields via the following rules:

Parameters

Source Group

A subset of the source geometry where attribute values are transferred from.

Source Group Type

The type of elements referenced in Source Group.

Destination Group

A subset of the destination geometry where attribute values are transferred to.

Destination Group Type

The type of elements referenced in Destination Group.

Attributes

Detail

Source detail attributes to transfer.

Primitives

Source primitive attributes to transfer.

Points

Source point attributes to transfer.

Vertices

Source vertex attributes to transfer.

Copy Local Variables

When turned on, all local variables referring to the copied attributes are also copied.

Allow P Attribute

When turned on, patterns used in the Points parameter can match the P attribute. Otherwise, the P attribute will be ignored even if it matches the pattern.

Conditions

The Conditions tab contains several parameters that control how the source attributes are combined or filtered to give the resulting destination values.

Kernel Function

The interpolating metaball kernel. The kernels are parameterized by distance and typically give more weight to source points/primitives/vertices that are closer.

Kernel Radius

The drop-off radius for the kernel function. As the kernel radius approaches zero, the filter resembles nearest neighbor interpolation. As the kernel radius increases, the filter approaches uniform weighting.

Max Sample Count

The maximum number of points/primitives/vertices to interpolate from. A maximum sample count of 1 gives nearest neighbor interpolation.

Distance Threshold

The maximum distance that the source points/primitives can be at to be considered. Switching off this option indicates that no points/primitives will be excluded based on distance. Within the distance threshold, the final attributes are determined solely from the source selection. In cases where all source points/primitives/vertices lie beyond the distance threshold, the destination attributes remain unchanged.

Blend Width

Relaxes the distance threshold and optionally sets a region outside the Distance Threshold where the influence of the source attributes gradually tapers off. In this region, the interpolated source attribute value is blended with the original destination attribute value using the selected Kernel Function to produce the interpolation factors. In this blending process, the Blend Width is used as the kernel radius. In regions outside the Distance Threshold + Blend Width, the destination attributes remain unchanged.

Uniform Bias

Specifies the linear interpolation factor that is used when blending with the Uniform Model Kernel Function. The Uniform Bias value is used as the source blending factor, whereas the destination blending factor is set to '1 - Uniform Bias'.

Examples

NormalsAttribTransfer Example for Attribute Transfer geometry node

The AttribTransfer SOP may be used to transfer various point attributes from a source geometry to a target. In this case, the normal attributes, N[3], of one grid are transferred to another grid.

TransferColor Example for Attribute Transfer geometry node

The Attribute Transfer SOP can be used to transfer color attributes from one geometry to another. The effective field of transfer can be controlled through the various parameters in the Attribute Transfer SOP.

See also

Geometry nodes