Pyro Light Scatter Copernicus node

Builds a light field of internal glow of a VDB.

On this page	Parameters Quality Inputs Outputs
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 produced by internal scattering from an internal emission within a VDB. This can be used to create a rich glow that appears to emerge from the center of dense smoke.

Multiple Pyro Light Scatter nodes 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 the VDB as lit smoke.

Parameters ¶

Density Scale

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

Absorption

Controls how quickly emitted light is absorbed by the smoke particles instead of being scattered further through the volume.

Emission Scale

Applies a global scale to the incoming emission VDB.

Emission Color Ramp

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

Iterations

Controls how many diffusion iterations are performed when scattering light through the volume. The emission is treated as a source term during diffusion. Although the process eventually converges, it is typically stopped early to keep it fast and to adjust the look.

Quality ¶

MipMap Level

Controls the MipMap level used for the light scattering computation. A mipmap level of 1 computes at half the original resolution and halves the number of iterations, making the process approximately 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.

Parameters ¶

Quality ¶

Inputs ¶

Outputs ¶

Copernicus nodes