Houdini 21.0 Nodes Copernicus nodes

Pyro Light Scatter Copernicus node

Builds a light field of internal glow of a VDB.

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Since 21.0

This operation constructs a light field that stores the intensity of light that originates from internal scattering within a VDB from an internal emission. This can be useful to provide a rich glow coming out of the center of a dense smoke.

Light operations can be chained together to accumulate multiple light sources and used as an input to the Rasterize Volume COP a VDB as lit smoke.

Parameters

Density Scale

Scales the density VDB values, causing it to occlude light swifter.

Absorption

As the emitted light scatters within the smoke, this is how quickly it gets absorbed by the smoke particles directly rather than scattered onward.

Emission Scale

A global scale on the incoming emission VDB.

Emission Color Ramp

The emission VDB is sent through this ramp to generate an emission color.

Iterations

Scattering is done by diffusing light through the volume with the emission treated as a source term. This should eventually converge, but to keep it fast and to adjust the look, the process is usually stopped early.

Quality

MipMap Level

The MipMap level. MipMap level 1 will compute at half resolution and also cut the iterations in half; making the process sixteen times faster. The final scatter values are the interpolated back to the original resolution.

Inputs

density

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

emission

A Float VDB storing the emission. This is scaled by the global emission and remapped to a color to form the actual emission source.

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.

Outputs

light

The light that reaches each voxel from the emission sources.

See also

Copernicus nodes