Houdini 20.5 Nodes Geometry nodes

Transform By Attribute geometry node

Transforms the input geometry by a point attribute.

Since 14.5

Unlike the Transform SOP, the transform applied to each point will be different, and be governed by a point attribute.

This is useful to apply a deformation to all attribute types. An Attribute VOP SOP may be used to create a deformation attribute, and then this node can apply it to the relevant attribute types.

Primitives attached to the points will also by transformed, allowing volumes and packed primitives to transform as expected.

A deformer can either be written by leaving P unaffected and generating a full 4×4 matrix on each point in VOPs. Then this node will perform the actual deformation across all attribute types. You can also deform P in the VOP code, but output a 3×3 matrix representing the local derivatives of the transform, allowing vectors such as up and v to properly reorient. If you want to enforce a pure rotation, use the polardecomp function.

Parameters

Group

Point group to transform.

Group Type

The type of elements referenced in the Group field.

Transform Attribute

A point attribute to use as the transform at each point.

This should be a float attribute. The size of the attribute determines the type of transformation.

3

Translation by a delta. Only affects attributes with point and hpoint type info.

4

Rotation by a quaternion. Does not affect attributes with point or hpoint type info.

9

Multiplication by a 3×3 transform matrix. Does not affect attributes with point or hpoint type info.

16

Multiplication by a 4×4 transform matrix. 4×4 detail attributes are also supported.

Attributes to Transform

Point and Vertex attributes that match this pattern will be transformed. Their Type Info will be used to determine how they should transform, as points, vectors, and normals all need different operations.

If P matches this string, then primitive transforms will also be rotated.

In no case is the transform attribute itself transformed.

Invert Transformation

When enabled, the inverse of the transform will be applied, instead of the transform itself.

Recompute Affected Normals

Recomputes any normals that are affected by polygons that use both transformed and untransformed points. When transforming the full geometry or full connected components, the results should be the same as when this option is off, i.e. the normals will just be transformed and not recomputed. This does nothing if P is not being transformed.

Preserve Normal Length

Normal lengths remain unaffected.

Delete Transform Attribute

The transform attribute is deleted after being used.

See also

Geometry nodes