Houdini 22.0 Nodes Copernicus nodes

Pyro Light from Points Copernicus node

Builds a light field of points lighting a VDB.

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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.

This node constructs a light field that stores the intensity of light reaching each voxel. The source of the light is point lights specified as an input or a parameter.

Multiple light operations can be chained together to accumulate light from multiple sources. The resulting light field can be used as an input to the Rasterize Volume COP node to render a VDB as lit smoke.

Parameters

Light Type

Directional

When turned on, the light is considered to be at infinity and all light rays are parallel. If point geometry is used as the source, the direction from each point to the origin defines the light direction.

When turned off, the lights are treated as point lights that emanate from their 3D positions.

Light Position

When no point geometry is provided, specifies the center of the light when it is not directional.

Light Direction

When no point geometry is provided, specifies the direction of the light when it is directional.

Light Radius

Point lights have a singularity at their location, so if a point light is inside the volume it becomes infinitely bright at that location. This regularizes the falloff by treating the light as a sphere with the specified radius.

This value is multiplied by the pscale point attribute.

Shading

Color

The color of the light. This value is multiplied by the Cd point attribute.

Intensity

Controls the linear brightness of the light.

Exposure

Controls the exponential brightness of the light. Each increase of 1 doubles the brightness.

Density Scale

Scales the density VDB values, causing the volume to occlude light more quickly.

Quality

Steps Per MipMap

Controls how many tracing steps are performed before dropping to the next MipMap level when tracing occlusion rays. This causes the rays to become cones, producing blurrier shadows farther from the light source.

Max Steps

Controls the maximum number of samples taken while tracing an occlusion ray. Since higher MipMap levels have larger step sizes, the distance covered will be larger than just the voxelsize times the maxsteps.

Inputs

density

A Float VDB storing the density to occlude light. This is also the topology used to build a light field. The light field will only be present where density was activated.

mipmap

An optional Float VDB MipMap from a Packed MipMap COP. If not provided, it will be computed internally.

light

An optional Vector VDB storing the amount of illumination at each voxel. The new light will be added to this, allowing lights to be chained.

points

An optional Geometry whose points will be treated as light sources. Every point needs to be cast against every voxel, so care should be taken not to use too many points.

Outputs

light

The light that reaches each voxel from the ambient sources.

See also

Copernicus nodes