Pyro Dissipate Copernicus node

Dissipates a VDB’s values over time.

On this page	Parameters Control Mask Axis Mask Limit Values Inputs Outputs
Since	21.0

Note

Although COP Pyro is in COPs, you need DOP level permissions to use it. This means that COP Pyro is not available in Houdini Core, but only in Houdini FX, Houdini Apprentice, Houdini Indie, and Houdini Education.

The Pyro Dissipate COP performs several types of dissipation on the input VDB. This will drive the VDB’s value to the goal value (usually zero), causing the smoke to disappear over time. An optional control field can be used to affect where the dissipation occurs.

Parameters ¶

Signature

The VDB type that the source accepts.

See Signatures for more information.

Mode

Controls the rate by which to dissipate the VDB.

Dissipation Rate

The percentage of the current amount to be lost per fixed interval (per second).

Subtraction Rate

Specific amount to be lost per fixed interval (per second).

Lifespan

The interval (per second) in which a fixed amount (1 unit) to be lost.

Half-Life

The interval (per second) in which half the amount to be lost (half-life).

Dissipation Rate

The percentage of the current amount to be lost per fixed interval (per second).

Subtraction Rate

Specific amount to be lost per fixed interval (per second).

Lifespan

The interval (per second) in which a fixed amount (1 unit) to be lost.

Half-Life

The interval (per second) in which half the amount to be lost (half-life).

Goal Value

The reference value to which the field will cool to, usually zero.

Goal Tolerance

When turned on and the VDB’s value cools below Goal Value + Goal Tolerance, the VDB’s value will be driven down all the way to the Goal Value.

Control Mask ¶

Control Volume

Mask out the effect using the control field. Control fields are usually used the same way as masks, and represent a smooth engagement of the effect.

Control Range

The value of the control field is mapped from this range to 0-1 and applied as a multiplier on top of Scale. The default 0 to 1 range is designed to concentrate the effect on regions with higher control field values. When the control field is a Vector VDB, this value represents the length of the given vector field.

Use Ramp

Turns on the Control Ramp, to change how the control field should scale the effect between the minimum and maximum values of Control Range.

Control Ramp

This ramp controls how the control field values are mapped between the minimum and maximum values of Control Range.

Axis Mask ¶

Axis Mask

Mask out the effect along an axis direction. Rather than requiring the construction of VDBs to represent this, this allows direct specification of the world space range over which the effect is to be scaled.

Axis Direction

The reference vector along which the effect will be masked.

Axis Range

The position along the axis mask is mapped from this range to 0-1 and applied as a multiplier on top of Scale.

Use Ramp

Turns on the Axis Control Ramp, to change how the position along the axis should scale the effect between the minimum and maximum values of Axis Range.

Axis Control Ramp

This ramp controls how the position is mapped between the minimum and maximum values of Axis Range.

Limit Values ¶

Minimum Limit

The output VDB is clamped below by this value.

Maximum Limit

The output VDB is clamped above by this value.

Inputs ¶

source

A Float VDB or Vector VDB to drive to a goal value.

control

A Float or Vector VDB to use as a control field. If it is a Vector VDB, its length is used.

Outputs ¶

dissipate

The input VDB dissipated.

Parameters ¶

Control Mask ¶

Axis Mask ¶

Limit Values ¶

Inputs ¶

Outputs ¶

Copernicus nodes