Houdini 20.5 Nodes Geometry nodes

Shape Diff geometry node

Computes the post-deform or pre-deform difference of two geometries with similar topologies.

On this page
Since 17.0

Overview

This node computes the post-pose deform or pre-pose deform difference of two geometries: rest and example. The geometries must have the same number of vertices and have a similar topology. The post-deform difference method returns the difference vectors between the input geometries. Identical vertices become zero vectors. The pre-deform difference method first transforms the example geometry to the rest-pose by applying inverse skinning method to the deformed geometry. The example geometry has been deformed and edited this node returns the difference vectors as though they were made to the pre-deformed example geometry.

Parameters

Difference Method

Pre-Deform

Transforms the example geometry into the rest-pose by applying inverse skinning method to the example geometry before computing the difference.

Post-Deform

Computes the difference of specified attribute on the two geometries.

Post-Deform Orient

Produces a similar result as the Pre-Deform method however instead of transforming the example geometry with inverse skinning this method transforms each point by the inverse of the orientation indicated by a quaternion point attribute.

From Input Geometry

When selected the shapeDiffMethod global attribute gives the difference method where the string value predeform specifies Pre-Deform differencing, postdeform specifies Pose-Deform differencing, and postdeform_orient specifies Post-Deform Orient differencing. The shapeDiffOrientAttrib global attribute also gives the Orient Attribute name.

Orient Attribute

The name of the quaternion point attribute to use with the Post-Deform Orient difference method.

Skeleton Root Path

Specifies the parent OBJ for the bones attached to the input geometry. The pCaptSkelRoot detail attribute is used by default when this parameter is empty. If this parameter is non-empty, it overrides the pCaptSkelRoot detail attribute in the input geometry. Relative path values here will be with respect to this node.

Transforms Path

An optional path to a CHOP node that contains channels for the world bone transforms, overriding the current state of the bones. In CHOPs, the Extract Bone Transforms node can be used to capture the bone transforms.

The deformTransformsPath detail attribute is used by default when this parameter is empty. If this parameter is non-empty, it overrides the deformTransformsPath detail attribute in the input geometry.

Skinning Method

Dual Quaternion Blend Attribute

The name of the point attribute to use with the Blend Dual Quaternion and Linear skinning method.

Deform Normals

Deforms the point normals to match the deformation of the points.

Deform Vector Attributes

Deforms the vector attributes to match the deformation of the points.

Vector Attributes

Vector attributes to deform.

Deform Quaternion Attributes

Deforms the quaternion attributes to match the deformation of the points.

Quaternion Attributes

Quaternion attributes to deform.

Mask Attribute

Attribute of the mask from the second input to be used. The first (red) component is used as mask value.

Mask Scale

Scales the mask to reduce its effect globally.

See also

Geometry nodes