Houdini 20.5 Nodes Geometry nodes

Pyro Source geometry node

Creates points for sourcing pyro and smoke simulations.

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Since 17.0

The Pyro Source SOP converts its input geometry into points suitable for sourcing pyro and smoke simulations. This SOP adds specified attributes to the generated points, which can be rasterized and imported into desired DOP fields by the Volume Source node. Pyro Source also contains a handful of initialization presets for driving common simulation scenarios.

Inputs

Geometry to Source From

Input geometry. When Mode is set to Surface Scatter or Volume Scatter, the geometry must correspond to a surface; in the latter case, the surface must also have a resolvable interior.

Rest Geometry

If provided, this geometry will be used to generate points. These points are then moved to conform with the current configuration of the deforming geometry.

Outputs

Particles

Generated points, with the assigned attributes.

Parameters

Group

When specified, only the subset of the input geometry corresponding to this group is used.

Group Type

What the Group is made of.

Initialize

Configures the node according to the selected preset. Source Burn and Source Fuel can be used to drive legacy and sparse pyro simulations, respectively, whereas Source Smoke is meant for smoke simulations. Source Color creates color (Cd) and color density (Alpha) attributes that can be imported by the Volume Source node using the Blend operation.

Mode

Controls which points are exported by the node.

Surface Scatter

Points are scattered on the surface of the input geometry.

Keep Input

Points of the incoming geometry are used unchanged.

Volume Scatter

Points are scattered in the interior of the input geometry.

Particle Separation

When Mode is set to Surface Scatter or Volume Scatter, this parameter controls the density of seeded points; in Keep Input mode, value of Particle Separation is only used to calculate the pscale point attribute.

Particle Scale

Controls the scale of exported points. The pscale attribute is set to the product of Particle Separation and Particle Scale.

Note

If the input already contains a pscale attribute, the values will not be changed by this node.

Density Attribute

When mode is set to Surface Scatter, enabling this option allows you to select an attribute to control distribution of scattered points. More points will be generated in areas where values of the Density Attribute are larger.

Point Attributes

These point attributes will be interpolated from the input geometry to the generated points when Mode is set to Surface Scatter.

Vertex Attributes

These vertex attributes will be interpolated from the input geometry to the generated points when Mode is set to Surface Scatter.

Primitive Attributes

These primitive attributes will be interpolated from the input geometry to the generated points when Mode is set to Surface Scatter.

Detail Attributes

These detail attributes will be transferred from the input geometry to the generated points when Mode is set to Surface Scatter.

Deform Radius

Physical size of the neighborhood used for deforming the scattered points. Only available when a rest geometry is provided and Mode is set to Volume Scatter.

Minimum Points

If fewer than this number of points are found in the neighborhood for the purpose of deforming points, the search radius is increased. Only available when a rest geometry is provided and Mode is set to Volume Scatter.

Maximum Points

An upper bound on the neighborhood size used for deforming points. Only available when a rest geometry is provided and Mode is set to Volume Scatter.

Attributes

Count of numerical attributes to create for the exported points.

Attribute

The attribute to add to source points. The attribute can be selected from the list of commonly-used options or a custom one can be created.

Vector Attribute

This option can be turned on in Custom Attribute mode to create a vector-valued attribute; if disabled, a scalar attribute is added.

Name

Name of the created attribute.

Default Value

This value is used to initialize newly-created attributes. This parameter is not used for already-present point attributes.

Scale

The final exported value of the attribute is scaled by this value.

See also

Geometry nodes