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Attribute Transfer Node
Confirmed, NormalPublicDESIGN

Description

This is task is for a port of the "Data Transfer" modifier to a node.

Details
  • The "Mix Mode", "Mix Factor", and "Vertex Group" options can be removed, replaced by more attribute nodes after the transfer. This makes sense because the transfer of attributes between data should be the focus of this node, not what to do with them after.
  • Attributes are referred to by name. Therefore, a single attribute should be copied.
    • A later improvement to the node could be to copy multiple attributes, maybe with a multi-socket input node.
  • The "Generate Data Layers" operator can be removed, since it is not needed to create new data on the output geometry.
  • The "Domain" drop-down chooses which domain to create the result attribute on. The data type is chosen based on the source attribute.
  • The "Mapping" drop-down has a few options:
    • "Nearest": Copies attributes from the nearest element of the domain of the source attribute.
    • "Nearest Interpolated": Similar to what happens in the point distribute node, interpolates values from the nearest vertices or edges on the closest face
    • "Topology": Requires the topology of the target geometry to be the same, so really more of an "Attribute Copy" operation, otherwise outputs an error.
    • More options may be necessary based on the choice for the destination domain.
Further Questions
  • How many of the options are necessary for most use cases? The answer is unclear. More feedback is necessary from artists for this question.
    • The "Max Distance" and "Ray Radius" options may be necessary.
Implementation

It's not clear how much the existing data transfer code would be useful, my guess is not much.
The "Attribute Proximity" node already does the same thing with the "position" attribute, so some logic could be shared with that.

Event Timeline

As I understand it:

  • The Nearest mode of the modifier corresponds to the Points mode if the Attribute Proximity node
  • The Nearest Interpolated mode corresponds to the Faces mode

However the Attribute Proximity node only "transfers" position, so it's code would have to be extended to transfer arbitrary attributes (and interpolate them over triangle faces when needed).

Yes, good points. Those names in particular could be improved I think.

The way this is split up into details totally makes sense to me.
In terms of needed mapping methods I have a couple of thoughts:

  • How many options are necessary is quite difficult to say. Unfortunately, which option works best, can heavily rely on the specific case and topology.
  • At least there should probably also be a 'Projected' option
  • By far the biggest issue is the transfer on the Corner domain, with for example UV seams. Even the current operator/modifier works far from ideal in this case.
    • Having some method that is a bit smarter when handling split corners would be nice in general...

But I think additional needed methods can come if necessary.

Dalai Felinto (dfelinto) renamed this task from WIP: Attribute Transfer Node to Attribute Transfer Node.Apr 12 2021, 2:56 PM
Hans Goudey (HooglyBoogly) changed the task status from Needs Triage to Confirmed.Apr 12 2021, 11:51 PM
Hans Goudey (HooglyBoogly) claimed this task.
Hans Goudey (HooglyBoogly) updated the task description. (Show Details)