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| Since | 22.0 |
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.
This node is useful to source basic primitive shapes into a pyro simulation. By default, it can generate basic primitive shapes. Alternatively, you can connect a custom implicit surface to the implicitsurface input to use as the source.
Connect the output of this node to the source_points input of the 
Pyro Block Begin node. To use multiple sources, merge outputs from multiple instances into a 
Point Merge.
Parameters ¶
Activation
Turns this node on or off. This node is only active when this value is 1.
Shape ¶
Shape
Controls the type of shape to create.
Size
Controls the size of the box. Click the 
Per Component button for separate scale along each axis.
Size Scale
Controls the size of the box separately across each axis.
Roundness
Radius used to round the box edges. A value of 0 creates a sharp box.
Radius
Controls the size of the sphere. Click the Per Component button for separate scale along each axis.
Radius Scale
Controls the radius of the sphere separately across each axis.
Cut Sphere
When tunred on, cuts the sphere with a plane at the Y position specified by this parameter.
Radius
Major radius and tube radius of the torus.
Link Length
Stretches the torus into a chain link shape. A value of 0 creates a regular torus.
Length
Length of the tube along its local axis.
Radius
Radii at the two ends of the tube. Matching values create a straight tube; different values create a tapered tube.
Radius Scale
Uniform scale applied to the tube radii.
Round Caps
Rounds the tube ends.
Transform ¶
Translate
Controls the translation along the X, Y, and Z axes.
Rotate
Controls the rotation about the X, Y, and Z axes.
Uniform Scale
Controls the uniform scale of the shape.
Distortion Noise ¶
Distortion Noise
When turned on, distorts the source shape over time using generated noise. This can help add visual breakup to basic primitive shapes.
Amplitude
Controls the strength of the distortion along each axes.
Element Size
Controls the uniform scale of the noise elements.
Pulse Duration
Controls the rate at which the noise pattern changes. Set this to 0 to keep the noise pattern constant over time.
Roughness
The scale increment between iterations of fractal noise added to the basic output. The higher the value the larger the “jaggies” added to the output. You can use a negative value for roughness.
Seed
Defines the initial noise offset.
Sourcing ¶
Controls which fields are sourced from this shape and how they contribute to the simulation.
Density ¶
Source Density
When turned on, sources the shape into the density volume.
Source Mode
Controls when the source volume is mixed with the target volume.
Continuous
Sourcing remains active throughout the simulation and is applied on every solver step. Use this when you need a constant supply of density, temperature or other quantities.
First Frame Only
Sourcing is applied only on the first simulation frame. This is useful when the fluid is already present when the simulation begins. If the source is animated, those animations are ignored after the first frame.
Copy on First Frame
Sourcing remains active throughout the simulation, as in Continuous mode. On the first simulation frame, the source volume is copied into the target volume. On subsequent frames, the operation is determined by Operation.
Operation
Controls how the source volume is mixed with the target volume.
Add
The result is the sum of the source and target values.
Copy
The result is copied from the source volume.
Maximum
The result is the greater of the source and target values.
Average
The result is the average of the source and target values.
Blend
The result is a blend between the source and target values, using Blend as the weight.
Pull
Pushes source values toward the corresponding target values according to the Acceleration Strength and Deceleration Strength settings.
Scale
Scales the source values before they are mixed with the target volume.
Scale by Timestep
Scales the effect of sourcing by the timestep. This ensures that the amount of sourcing remains consistent when substepping occurs. Turn off this parameter if you need the instantaneous source value.
Blend
Controls the weight used to blend between the source values and the corresponding volume values.
Acceleration
Controls how strongly source values that are smaller than the corresponding target values are pushed toward the target field.
Deceleration
Controls how strongly source values that are larger than the corresponding target volume values are pushed toward the target field.
Scale by Noise ¶
Enable Noise
When turned on, multiplies the uniform source value by a generated noise pattern.
Scale Min/Max
Sets the minimum and maximum values of the noise range. To create larger empty spaces, lower the minimum value to negative numbers and turn on Avoid Negatives.
Avoid Negatives
When this is on, negative values will be set to zero.
Element Size
Controls the base feature size of the generated noise. This applies uniformly to each axis.
Pulse Duration
Controls the rate at which the noise pattern changes. Set this to 0 if static noise is required.
Roughness
Controls the scale increment between iterations of the fractal noise. Higher values produce finer detail, while lower values produce a smoother noise field.
Seed
Defines the initial noise offset.
Temperature ¶
Source Temperature
When turned on, the shape is sourced into the temperature volume.
Source Mode
Controls when the source volume is mixed with the target volume.
Continuous
Sourcing remains active throughout the simulation and is applied on every solver step. Use this when you need a constant supply of density, temperature or other quantities.
First Frame Only
Sourcing is applied only on the first simulation frame. This is useful when the fluid is already present when the simulation begins. If the source is animated, those animations are ignored after the first frame.
Copy on First Frame
Sourcing remains active throughout the simulation, as in Continuous mode. On the first simulation frame, the source volume is copied into the target volume. On subsequent frames, the operation is determined by Operation.
Operation
Controls how the source volume is mixed with the target volume.
Add
The result is the sum of the source and target values.
Copy
The result is copied from the source volume.
Maximum
The result is the greater of the source and target values.
Average
The result is the average of the source and target values.
Blend
The result is a blend between the source and target values, using Blend as the weight.
Pull
Pushes source values toward the corresponding target values according to the Acceleration Strength and Deceleration Strength settings.
Scale
Scales the source values before they are mixed with the target volume.
Scale by Timestep
Scales the effect of sourcing by the timestep. This ensures that the amount of sourcing remains consistent when substepping occurs. Turn off this parameter if you need the instantaneous source value.
Blend
Controls the weight used to blend between the source values and the corresponding volume values.
Acceleration
Controls how strongly source values that are smaller than the corresponding target values are pushed toward the target field.
Deceleration
Controls how strongly source values that are larger than the corresponding target volume values are pushed toward the target field.
Scale by Noise ¶
Enable Noise
When turned on, multiplies the uniform source value by a generated noise pattern.
Scale Min/Max
Sets the minimum and maximum values of the noise range. To create larger empty spaces, lower the minimum value to negative numbers and turn on Avoid Negatives.
Avoid Negatives
When this is on, negative values will be set to zero.
Element Size
Controls the base feature size of the generated noise. This applies uniformly to each axis.
Pulse Duration
Controls the rate at which the noise pattern changes. Set this to 0 if static noise is required.
Roughness
Controls the scale increment between iterations of the fractal noise. Higher values produce finer detail, while lower values produce a smoother noise field.
Seed
Defines the initial noise offset.
Velocity ¶
Source Velocity
When turned on, the shape is sourced into the velocity volume.
Source Mode
Controls when the source volume is mixed with the target volume.
Continuous
Sourcing remains active throughout the simulation and is applied on every solver step. Use this when you need a constant supply of density, temperature or other quantities.
First Frame Only
Sourcing is applied only on the first simulation frame. This is useful when the fluid is already present when the simulation begins. If the source is animated, those animations are ignored after the first frame.
Copy on First Frame
Sourcing remains active throughout the simulation, as in Continuous mode. On the first simulation frame, the source volume is copied into the target volume. On subsequent frames, the operation is determined by Operation.
Operation
Controls how the source volume is mixed with the target volume.
Add
The result is the sum of the source and target values.
Copy
The result is copied from the source volume.
Maximum
The result is the greater of the source and target values.
Average
The result is the average of the source and target values.
Blend
The result is a blend between the source and target values, using Blend as the weight.
Pull
Pushes source values toward the corresponding target values according to the Acceleration Strength and Deceleration Strength settings.
Scale
Scales the source values before they are mixed with the target volume.
Scale by Timestep
Scales the effect of sourcing by the timestep. This ensures that the amount of sourcing remains consistent when substepping occurs. Turn off this parameter if you need the instantaneous source value.
Blend
Controls the weight used to blend between the source values and the corresponding volume values.
Acceleration
Controls how strongly source values that are smaller than the corresponding target values are pushed toward the target field.
Deceleration
Controls how strongly source values that are larger than the corresponding target volume values are pushed toward the target field.
Inherited Velocity ¶
Point Velocity
When turned on, calculates the velocity of the implicit surface from its motion using the Velocity Approximation parameter. This is useful for moving or rotating sources.
Velocity Scale
Scales the strength of the velocity calculated from the motion.
Force ¶
Enable Force
When turned on, calculates an additional force field that can push quantities away from or around the source shape.
Force Type
Controls the type of force added to the velocity field.
Directional
Applies a uniform velocity throughout the field. All vectors point in the direction specified by the Direction.
Spherical
Calculates the velocities based on the distance from a center point. Vectors point outward from the shape.
Spin
Creates a vortex field. Vectors are calculated perpendicular to the center of the source, causing motion to spiral around the axis specified by the Axis.
Radial
Generates vectors that point away from the line defined by the Axis, which passes through the center of the source, spreading outward across the volume.
Scale
Scales the strength of the calculated velocity force.
Direction
When Force Type is set to Directional, specifies the direction in which all velocity vectors point.
Axis
When Force Type is set to Spin, this controls the direction of rotation. Just like a wheel, the axis is the invisible pole the velocity vectors spin around.
When Force Type is set to Radial, defines the orientation of the line from which the velocity vectors point away.
Curl Noise ¶
Noise
When turned on, calculates an additional vector field based on a generated noise pattern.
Amplitude
Controls the strength of the calculated noise field.
Element Size
Controls the base feature size of the generated noise. This applies uniformly to each axis.
Pulse Duration
Controls the rate at which the noise pattern changes. Set this to 0 if static noise is required.
Roughness
Controls the scale increment between iterations of the fractal noise. Higher values produce finer detail, while lower values produce a smoother noise field.
Seed
Defines the initial noise offset.
Flame ¶
Source Flame
When turned on, the shape is sourced into the flame volume.
Source Mode
Controls when the source volume is mixed with the target volume.
Continuous
Sourcing remains active throughout the simulation and is applied on every solver step. Use this when you need a constant supply of density, temperature or other quantities.
First Frame Only
Sourcing is applied only on the first simulation frame. This is useful when the fluid is already present when the simulation begins. If the source is animated, those animations are ignored after the first frame.
Copy on First Frame
Sourcing remains active throughout the simulation, as in Continuous mode. On the first simulation frame, the source volume is copied into the target volume. On subsequent frames, the operation is determined by Operation.
Operation
Controls how the source volume is mixed with the target volume.
Add
The result is the sum of the source and target values.
Copy
The result is copied from the source volume.
Maximum
The result is the greater of the source and target values.
Average
The result is the average of the source and target values.
Blend
The result is a blend between the source and target values, using Blend as the weight.
Pull
Pushes source values toward the corresponding target values according to the Acceleration Strength and Deceleration Strength settings.
Scale
Scales the source values before they are mixed with the target volume.
Scale by Timestep
Scales the effect of sourcing by the timestep. This ensures that the amount of sourcing remains consistent when substepping occurs. Turn off this parameter if you need the instantaneous source value.
Blend
Controls the weight used to blend between the source values and the corresponding volume values.
Acceleration
Controls how strongly source values that are smaller than the corresponding target values are pushed toward the target field.
Deceleration
Controls how strongly source values that are larger than the corresponding target volume values are pushed toward the target field.
Scale by Noise ¶
Enable Noise
When turned on, multiplies the uniform source value by a generated noise pattern.
Scale Min/Max
Sets the minimum and maximum values of the noise range. To create larger empty spaces, lower the minimum value to negative numbers and turn on Avoid Negatives.
Avoid Negatives
When this is on, negative values will be set to zero.
Element Size
Controls the base feature size of the generated noise. This applies uniformly to each axis.
Pulse Duration
Controls the rate at which the noise pattern changes. Set this to 0 if static noise is required.
Roughness
Controls the scale increment between iterations of the fractal noise. Higher values produce finer detail, while lower values produce a smoother noise field.
Seed
Defines the initial noise offset.
Divergence ¶
Source Divergence
When turned on, the shape is sourced into the divergence volume.
Source Mode
Controls when the source volume is mixed with the target volume.
Continuous
Sourcing remains active throughout the simulation and is applied on every solver step. Use this when you need a constant supply of density, temperature or other quantities.
First Frame Only
Sourcing is applied only on the first simulation frame. This is useful when the fluid is already present when the simulation begins. If the source is animated, those animations are ignored after the first frame.
Copy on First Frame
Sourcing remains active throughout the simulation, as in Continuous mode. On the first simulation frame, the source volume is copied into the target volume. On subsequent frames, the operation is determined by Operation.
Operation
Controls how the source volume is mixed with the target volume.
Add
The result is the sum of the source and target values.
Copy
The result is copied from the source volume.
Maximum
The result is the greater of the source and target values.
Average
The result is the average of the source and target values.
Blend
The result is a blend between the source and target values, using Blend as the weight.
Pull
Pushes source values toward the corresponding target values according to the Acceleration Strength and Deceleration Strength settings.
Scale
Scales the source values before they are mixed with the target volume.
Scale by Timestep
Scales the effect of sourcing by the timestep. This ensures that the amount of sourcing remains consistent when substepping occurs. Turn off this parameter if you need the instantaneous source value.
Blend
Controls the weight used to blend between the source values and the corresponding volume values.
Acceleration
Controls how strongly source values that are smaller than the corresponding target values are pushed toward the target field.
Deceleration
Controls how strongly source values that are larger than the corresponding target volume values are pushed toward the target field.
Scale by Noise ¶
Enable Noise
When turned on, multiplies the uniform source value by a generated noise pattern.
Scale Min/Max
Sets the minimum and maximum values of the noise range. To create larger empty spaces, lower the minimum value to negative numbers and turn on Avoid Negatives.
Avoid Negatives
When this is on, negative values will be set to zero.
Element Size
Controls the base feature size of the generated noise. This applies uniformly to each axis.
Pulse Duration
Controls the rate at which the noise pattern changes. Set this to 0 if static noise is required.
Roughness
Controls the scale increment between iterations of the fractal noise. Higher values produce finer detail, while lower values produce a smoother noise field.
Seed
Defines the initial noise offset.
Inputs ¶
implicitsurface
An implicit surface geometry built using the SOP based implicit surface workflow.
Outputs ¶
source_points
Points representing implicit surface with pyro source attributes.
| See also |
Pyro Source from Shape
Pyro Collision Shape
