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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.
If you want to copy attributes between models with the same topology, use Attrib Copy instead, because it’s much faster.
If you wire the same geometry into both inputs of this node, you can use it to "blur" attributes across surfaces.
Use Attribute Promote when you want to copy attributes between geometry in the same stream (it has one input). Use Attribute Transfer when you want to copy attributes on geometry in one input onto geometry in another input.
The attributes may be explicitly specified in the corresponding attribute text field. Exclusion is specified by preceding an attribute name with the caret character (^). All available attributes can be specified by leaving the field blank or entering an asterisk (*) in the field. If the first attribute is preceded by a caret then all attributes are assumed to be transferred except where explicitly excluded. In all other cases, no attributes are assumed except where explicitly included.
Destination attributes are interpolated from the source attributes using a weighted proximity technique. Proximities used in point attribute calculations are determined as the distance between the destination point and the candidate source points. For primitive attribute calculations, the barycenter-to-barycenter distance between the destination primitive and the candidate source primitives is used. In the case of vertex attributes, each destination vertex is first mapped to the closest position and primitive in the source geometry. The vertex attribute is then determined using a barycentric-like interpolation technique. The source detail attribute is simply copied to the destination detail attribute.
The Conditions tab contains several parameters that control how the source attributes are combined, or filtered, to give the resulting destination values. The Kernel Function can be set to any available metaball kernel. The kernels are parameterized by distance and typically give more weight to source points/primitives/vertices that are closer. The Max Sample Count parameter specifies the maximum number of points/primitives/vertices to interpolate from. A maximum sample count of 1 gives nearest neighbor interpolation. The Kernel Radius specifies the drop-off radius for the kernel function. As the kernel radius parameter approaches zero, the filter resembles nearest neighbor interpolation. As the kernel radius parameter increases, the filter approaches uniform weighting. The Distance Threshold parameter specifies the maximum distance source points/primitives must be 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. The Blend Width parameter 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. The Uniform Bias parameter specifies the linear interpolation factor that is used when blending with the Uniform kernel function. The Uniform Bias value is used as the source blending factor, whereas the destination blending factor is set to one minus this value.
A subset of the source geometry where attribute values are transferred from.
Source Group Type
The type of elements referenced in the Source Group field.
A subset of the destination geometry where attribute values are transferred to.
Destination Group Type
The type of elements referenced in the Destination Group field.
Source detail attributes to transfer.
Source primitive attributes to transfer.
Source point attributes to transfer.
Source vertex attributes to transfer.
Copy Local Variables
All local variables referring to the copied attributes are also copied.
Match P Attribute
If enabled, patterns used in the Points parameter can match the
Interpolating metaball kernel .
Max Sample Count
Number of closest samples to interpolate from.
Radial extent of the kernel function.
Radial extent of the filter domain where the final attributes are determined from the source selection only.
The radial extent beyond the distance threshold where the final attributes are blended from the source and destination selections using the Kernel Function and the Blend Width as the kernel radius. In regions outside the Distance Threshold + Blend Width, the destination attributes remain unchanged.
The linear interpolation factor that is used when blending with the Uniform kernel function. This value is used for the source, whereas the destination factor is set to '1 - Uniform Bias'.
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, of one grid are transferred to another grid.