The Attribute node is used to create or promote attributes in the flow. New attributes can be used to control parameters via expressions or to pass information to the renderer via mapping.
| Input | Type | Description |
|---|
| 0 | Data Flow | Particles, Fibres, Feathers and Meshes |
| 1 | Strands | Groom/Guide Curves which may have an attribute painted to be sampled. |
Parameters
| Parameter | Description |
|---|
| Attribute | The name of the attribute, if it already exists then it will be modified - otherwise it will be created. |
| Default | Default value for the attribute. |
| Attribute Type | The data type for the new attribute. |
| Detail Type | Constant = Per Object, Uniform = Per Element, Varying = Per Span and Vertex = Per Vertex. |
Mapping
Attribute mapping is a way of telling Yeti that the desired attribute needs to be passed to the rendering engine, possibly to be used for shading or to control renderer specific parameters.
| Parameter | Description |
|---|
| Map As Renderable Attribute | This will map a named attribute to a renderable attribute. If on Yeti will output either the new attribute or an attribute specified below to the renderer. |
| Attribute | The name of the attribute to map. |
| Mapping | The name of the attribute as it should be passed to the renderer, if left blank it will use it's current name. |
Groom
Yeti grooms allows users to paint additional attributes across the strands, these groom attributes can then be sampled by the Attribute node to set new attribute values.
| Parameter | Description |
|---|
| Sample Groom | Toggle on/off (default) groom sampling. |
| Groom Attribute | The name of the attribute on the groom to use for sampling. |
| Interpolate Samples | Controls whether the grooms samples will interpolate multiple strand values (default) or just consider a single closest strand. |
Geometric
Helper parameters to create geometry based attributes that rely on the topology of the incoming data.
| Parameter | Added Attribute | Description |
|---|
| Add Reference Position | PRef | This will store the current position as a PRef vector attribute. |
| Add Root Position | surf_P | Will create a Yeti attribute called root which will be passed to the render engine as surf_P. This is a vector that represents the base of the fibre. |
| Add Tangent | tangent | Tangent of the fibre at the vertex being evaluated. |
| Add Face Index | faceindex | Index of the face the fibre/particle was create. |
| Add Per Vertex Texutre Coordinates | vtxcoord | Baked input mesh facevarying texture coordinates into per vertex values. |
| Add Arc Length | arcLength | Computed the arc length the input fibres. |
| RiCurve Basis | N/A | Can be used to control what basis function is used when exporting the curves to a Renderman compliant renderer. |