Houdini 21.0 Nodes Dynamics nodes

Gas Burn dynamics node

A microsolver that burns up the flame field.

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Since 21.0

Overview

The Gas Burn DOP is a microsolver used in building larger fluid simulations. The Fluid Solver and Smoke Solver DOPs allow microsolvers to be added before or after the main solver step to extend or tweak the simulation. Alternatively, advanced users may attempt to build an entire new solver out of microsolvers.

The Gas Burn DOP controls the dissipation of the flame field in the Pyro Solver. It is also able to emit smoke and temperature into the simulation based on the dissipated flame amount. Additionally you can use the flame field to add divergence into the simulation causing expansion.

Parameters

Time Scale

A scaling factor for time inside this solver. 1 is normal speed, greater than 1 speeds up the simulation, while less than 1 slows it down.

Cooling

Enable Cooling

Controls when to dissipate the flame field. When this is turned on, the amount of smoke, temperature, and expansion is scaled by the amount of dissipated flame.

Cool Source

Mode

Controls the rate by which to dissipate the field.

Dissipation Rate

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

Subtraction Rate

Specific amount lost per fixed interval (per second).

Lifespan

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

Half-Life

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

Dissipation Rate

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

Subtraction Rate

Specific amount lost per fixed interval (per second).

Lifespan

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

Half Life

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

Use Control Field

When turned on, the dissipation is scaled by the control field.

Control Field

The name of the field to use to affect dissipation.

Control Range

Remaps (normalizes) the Control Field values based on the specified minimum and maximum. The output is used for scaling is always in a range of 0 to 1.

Control Field Ramp

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

Use Bound Control

When turned on, the dissipation is scaled along one of the following directions.

Direction

Sets the direction along which to dissipate the field.

Bound Range

The minimum and maximum bounds along the set axis, in which the scale will remap to the range of 0 to 1.

Bound Control Ramp

This ramp controls how the dissipation scale values are mapped between the minimum and maximum values of Bound Range.

Smoke

Smoke Emission

When turned on, density is added to the Smoke Field, representing smoke in the simulation.

Emit Smoke

Operation

Controls how the output of the source field (given by Source Field) is mixed with the smoke field (given by Smoke Field).

Max

Larger of the two values is taken. This merge method ensures that smoke does not keep accumulating.

Add

Output of the source field (given by Source Field) is scaled by the timestep and added to the smoke field (given by Smoke Field).

Emission Scale

Amount of density output from the source field (given by Source Field). This parameter acts as a multiplier for the remapped source value.

Source Range

The range of values in the source field (given by Source Field) that will generate an output. The source field is first fitted from this range to 0-1. If Remap Source Range is turned on, the Source Ramp is then evaluated at this value. The final output is the product of this remapped source value and Emission Scale.

Remap Source Range

When turned on, Source Ramp is evaluated at the refitted source value (from Source Range to 0-1) to generate the output.

Source Ramp

This ramp controls how the density output values are mapped between the minimum and maximum values of Source Range.

Use Control Field

When turned on, the emitted smoke amount is additionally scaled by the control field.

Control Field

The name of the field to use to affect smoke output.

Control Range

The range values in the Control Field that will generate an output.

Remap Control Field

Remaps (normalizes) the Control Field values based on the specified minimum and maximum. The output that is used for scaling is always in a range of 0 to 1.

Control Field Ramp

Allows the Control Ramp to change how the control field should scale density output between the minimum and maximum values of Control Range.

Temperature

Temperature Emission

When turned on, temperature is added to the Temperature Field.

Emit Temperature

Operation

Controls how the output of the source field (given by Source Field) is mixed with the temperature field (given by Temperature Field).

Pull

Wherever output from the source field (given by Source Field) exceeds the temperature value, temperature is pushed towards the output. This merge method ensures that temperature does not keep accumulating.

Add

Output of the source field (given by Source Field) is scaled by the timestep and added to the temperature field.

Strength

How strongly the temperature field values are pushed towards the hotter source field, when Merge Method is set to Pull.

Emission Scale

Amount of temperature output from the source field. This parameter acts as a multiplier for the remapped source value.

Source Range

The range of values in the source field (given by Source Field) that will generate an output. The source field is first fitted from this range to 0-1. If Remap Source Range is turned on, the Source Ramp is then evaluated at this value. The final output is the product of this remapped source value and Temperature Amount.

Remap Source Range

When turned on, Source Ramp is evaluated at the refitted source value (from Source Range to 0-1) to generate the output.

Source Ramp

This ramp controls how the temperature output values are mapped between the minimum and maximum values of Source Range.

Use Control Field

When turned on, the emitted temperature amount is additionally scaled by the control field.

Control Field

The name of the field to use to affect temperature output.

Control Range

The range values in the Control Field that will generate an output.

Remap Control Field

Remaps (normalizes) the Control Field values based on the specified minimum and maximum. The output is used for scaling is always in a range of 0 to 1.

Control Field Ramp

Enables the Control Ramp to change how the control field should scale temperature output between the minimum and maximum values of Control Range.

Expansion

Enable Expansion

When turned on, goal divergence is added to the simulation in the specified Source Range, causing expansion.

Expansion

Expansion Rate

Controls the amount of divergence from the source field (given by Source Field). Larger values result in a more violent expansion. Negative values cause the gas to be sucked inwards (instead of blown outwards).

Source Range

The range of values in the source field (given by Source Field) that will generate an output. The source field is first fitted from this range to 0-1. If Remap Source Range is turned on, the Source Ramp is then evaluated at this value. The final output is the product of this remapped source value and Expansion Rate.

Remap Source Range

When turned on, Source Ramp is evaluated at the refitted source value (from Source Range to 0-1) to generate the output.

Expansion Ramp

This ramp controls how the expansion is mapped between the minimum and maximum values of Source Range.

Use Control Field

When turned on, the expansion is additionally scaled by the control field.

Control Field

The name of the field to use to affect the expansion.

Control Range

The range values in the Control Field that will generate an output.

Remap Control Field

Remaps (normalizes) the Control Field values based on the specified minimum and maximum. The output is used for scaling is always in a range of 0 to 1.

Control Field Ramp

Allows the Control Ramp to change how the control field should scale the expansion between the minimum and maximum values of Control Range.

Bindings

Source Field

The name of the field that will burn up.

Smoke Field

The name of the field into which density will be added.

Temperature Field

The name of the field into which temperature will be added.

Expansion Field

The name of the field that controls expansion.

Stencil Field

A scalar field to use as a stencil for where to perform this node’s computations. Voxels whose stencil value strictly exceeds 0.5 will have the operation applied, while the rest will be left unchanged.

Note

If a stencil field isn’t provided or does not exist, the operation will be performed everywhere.

Advanced

Use OpenCL

Use the OpenCL device to accelerate computations.

See also

Dynamics nodes