As opposed to the Point op or other ops that manipulate control points (CVs), the Clay op operates on the primitive contours themselves, providing a direct, intuitive, and unconstrained way of reshaping geometry. Thus, rather than translating CVs to change the aspect of the primitive, the Clay op takes the inverse approach of repositioning the CVs to reflect the tug on the primitive’s skin.

The point that defines the area to be modified is called a "target point" or "target" for short. It is expressed as a (u,v) pair in the parametric space of the primitive and ranges between 0 and 1 in both U and V. The image of the target point on the primitive is a 3D point which Clay can displace in several ways. Furthermore, if the primitive is a surface, there is are options to pull only the point or a whole isoparametric curve in either U or V.

Clay does not refine the faces and surfaces unless asked to, so the complexity of the geometry does not increase. The area affected by the change varies with each primitive type and topology. In all cases it is possible to reduce the amount of change by inserting a Refine op before the Clay op and inserting detail around the target point. For other ways to increase the locality of the deformation as well as its sharpness, see U and V Sharpness below.

If a second input is present, it is possible to snap the target (u,v) point to an (s,t) point on the first primitive of the second input. Without a second input, the primitives can be made to snap to themselves. Moreover, the Clay op is able to snap the target to arbitrary points in space.

Both this op and the Align SOP can be used effectively as snapping tools and building blocks for curve networks. The main difference between the two ops is that Clay deforms the inputs partially, while Align translates and/or rotates the whole primitive.

The Clay op accepts a mix of any combination of face and surface types.

## Parameters

Group

Subset of faces or hulls to deform.

U/V toggles

Parametric direction(s) to deform along.

## U tab

U

Parametric location where the deformations occurs.

U Bias

Amount of pull on either side of the U value.

U Sharpness

Primitive sharpness in the displaced area.

## V tab

V

Parametric location where the deformations occurs.

V Bias

Amount of pull on either side of the V value.

V Sharpness

Primitive sharpness in the displaced area.

## Matrix

Overview

Point transformation is given by a matrix.

Transform Order

Order transformations are applied.

Rotate Order

Order rotations are applied.

Translate

Amount of translation along xyz axes.

Rotate

Amount of rotation about xyz axes.

Scale

Non-uniform scaling along xyz axes.

Pivot

Local pivot point for transformations.

## Vector

Overview

Point is translated along a vector.

Distance

Translation distance.

Normal

Translate along primitive normal at (u,v).

Direction

Translation vector if Normal is off.

## Point

Overview

Point is moved to an absolute xyz position in object space.

Coordinates

Location the point must snap to.

## Primitive

Overview

Point snaps to the (u,v) of the primitive in the 2nd input or to a (u,v) on itself if no 2nd input is present.

U and V

Parametric coordinates on the target primitive.

See also |