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
to properly reorient. If you want to enforce a pure rotation, use the
Point group to transform.
The type of elements referenced in the Group field.
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.
Translation by a delta. Only affects Point and HPoint attributes.
Rotation by a quaternion. Does not affect Point or HPoint attributes.
Multiplication by a 3×3 transform matrix. Does not affect Point or HPoint attributes.
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.
P matches this string, then primitive transforms will
also be rotated.
In no case is the transform attribute itself transformed.
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.