GATOR to Transfer Attributes Between Dissimilar Objects


Because attribute transfer is based on proximity of points, it works best between objects that are roughly the same size and shape. But what happens if you want to transfer attributes between dissimilar objects? For example, you might want to transfer some facial animation from a kangaroo to a giraffe.

In these situations, you have a choice: before transferring the attributes, you can either deform the source to match the target or deform the target to match the source. Which technique to choose depends on which is most convenient given the shapes in question. The exact steps also depend on whether there is an envelope that you want to transfer.

To deform the source to match the target (with no envelope)

  1. Deform the source into roughly the shape of the target, for example, by tweaking points. Make sure that corresponding areas are close enough to ensure a good transfer.
  2. Apply GATOR and transfer the attributes.
  3. If desired, you can refine the transfer by tweaking the source geometry. Just make sure that the GATOR node is reading from the source’s construction history above the point where you are adding tweaks.
  4. Freeze the GATOR node.
  5. At this point, you can delete the source or, if you want to keep it, delete the deformation operators that you added.

To deform the source to match the target (with an envelope)

  1. Make sure that both the source and target are in their reference poses.
  2. If you want to keep the source, duplicate it or export it as an external model.
  3. Adjust the source skeleton to fit the target geometry by transforming bones, setting the bone length, or using the Move Joint tool. This has the effect of deforming the source geometry to roughly match the target.
  4. Perform any additional deformations you need to get the source geometry to match the shape of the target well enough to ensure a good transfer, for example, by tweaking points. Make sure to modify the source geometry in Secondary Shape construction mode so that your edits are applied above the envelope in the operator stack.
  5. Apply GATOR and transfer the attributes. If you tweaked the source in Secondary Shape mode, make sure that Inputs’ construction mode is set to Secondary Shape (Result). The target geometry may become distorted but that will be corrected in step 7.
  6. Freeze the GATOR node.
  7. Select the skeleton objects and reset their reference poses.
  8. Delete the source geometry.

To deform the target to match the source (with no envelope)

  1. Duplicate the target.
  2. Deform the target into roughly the shape of the source, for example, by tweaking points. Make sure that corresponding areas are close enough to ensure a good transfer.
  3. Apply GATOR and transfer the attributes.
  4. Freeze the GATOR node.
  5. Return the target to its original shape by selecting the duplicate as a shape key.
  6. Freeze the Cluster Shape Combiner node in the target’s operator stack.

To deform the target to match the source (with an envelope)

  1. Make sure that both the source and target are in their reference poses.
  2. If you want to keep the source, duplicate it or export it as an external model.
  3. Duplicate the target.
  4. Deform the target into roughly the shape of the source, for example, by tweaking points. Make sure that corresponding areas are close enough to ensure a good transfer.
  5. Apply GATOR and transfer the attributes.
  6. Freeze the GATOR node.
  7. Return the target to its original shape by selecting the duplicate as a shape key.
  8. Freeze the Cluster Shape Combiner node in the target’s operator stack.
  9. Delete the source geometry.
  10. Mute the target’s envelope operator, or set the viewports to display only the result of the Modeling construction region.
  11. Adjust the skeleton to fit the target geometry by transforming bones, setting the bone length, or using the Move Joint tool.
  12. Select both the target geometry and the skeleton, and reset their reference poses.
  13. Unmute the envelope.

This page was last modified 04:15, 15 Dec 2010.
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