Houdini 20.5 Nodes VOP nodes

Pyro Field VOP node

Since 12.0

This node may be used to create a user interface on a material for editing the values coming from a field or attribute.

It is designed as a higher-level “meta-parameter” similar to the Parameter VOP for values to be taken from a field or attribute. However, Houdini does not treat this node specially as it does the Parameter node, so to promote the UI for this node, you must choose Promote Interface ▸ UI + Links + Inputs to trigger scripts on the node to promote and create parameters up on the parent node.

Parameters

Field name

The name of a field such as density, or a local global (as on the Global Variables VOP such as P or v, or a VEX expression (not an Hscript expression) such as set(P.x, v.y, Pz).

Field Type

The required type of the incoming field.

Promote to type

Convert the incoming value from the field to a different data type. See the data type you want to convert to with the Output type parameter.

Method

How to fill in the extra components when converting to a data type with more components than the incoming type, for example converting a vector to a vector4. Or, what value to use when converting from

The following options are available when converting “up”.

Repeat last comp

Repeats the last component of the input. For example, converting a float 4.0 to a vector would give 4.0, 4.0, 4.0

Pad with 0s

Fills extra components with 0s. For example, converting a float 4.0 to a vector would give 4.0, 0.0, 0.0

Pad with 0s

Fills extra components with 1s. For example, converting a float 4.0 to a vector would give 4.0, 1.0, 1.0

Pad with constant

Fills extra components with the value of the Padding constant parameter.

The following options are available when converting from a vector to a float.

Component ‹n›

Use the value of the given component of the vector.

Min/Max/Average/Sum/Length

Use the given function to combine the components of the vector into a single value.

The following options are available when converting from a vector4 to a vector.

Truncate

Drop the last component of the vector4 to create a vector.

Dehomogonize

Divide the first three components by the fourth (W) component.

Fit to Range (unclamped)

Does a straight remapping of values in the field to target values without clamping the result.

Use lookup ramp

Remaps the values in the field according to a float or color ramp.

Contour

Increases or decreases contrast for values at the bottom of the input range. This is sometimes useful to control feathering in volume fields.

Soft Clip

Increases or decreases contrast for values at the top of the input range. This is sometimes useful to control feathering in volume fields.

Clamp to Min

Clamp outgoing values to this minimum.

Clamp to Max

Clamp outgoing values to this maximum.

Final amplitude

Scale the output of the above operations by this value.

Filter

The type of filtering to do on the output. “Point” is no filtering.

Scale

The scale of the filter effect, when Filter is “Box” or “Gaussian”.

See also

VOP nodes