Houdini 20.0 Nodes Geometry nodes

Pyro Post-Process 2.0 geometry node

Applies common post-processing effects to the results of Pyro solves.

Since 19.0

The Pyro Post-Process node provides common post-processing operations for Pyro solvers. It can also bake flame values into the density map to ensure Mantra picks up purely emissive regions.


Post Process

Compute Min/Max Values

Computes the minimum and maximum values of each volume and stores it as a primitive attribute of the same name. If the volume is vector type and is converted to VDB, the maximum length is stored.

Convert to VDB

Convert these volumes into VDBs. Zero areas will be discarded as inactive. Volume sets, such as vel.x, vel.y, and vel.z, will be merged into a single vector VDB.

Combine Volumes

When enabled, VDBs with the same name are combined into a single primitive. This feature is only available if volumes are converted to VDBs.

In areas where different volumes of the same name intersect, the maximum value is used for the combined result.

Use 16bit Float

Marks the volume to use 16-bit float values. This requires half the memory of full 32-bit values, but can be slower to process. Houdini volumes will be 16-bit in memory and on disk. VDBs are only 16-bit when saved to disk.

NOTE: For Houdini volumes this will only convert volumes to 16-bit, not convert back to 32-bit. Use the Volume Compress to switch volumes back to 32-bit.

Cull Volume

When enabled, the active region of the specified VDB will be restricted to the active region of the Cull Mask Volume. This can help reduce the memory footprint of the primitives while retaining the volume values in needed areas.

Resample Volumes

The names of volumes to resample. This is a space separated list of volume names and can contain wildcards. Note that volumes with suffixes (such as .x or .y) will match with and without the suffix. This way vel in this parameter will match with the volume named vel.x. Volumes whose names match this pattern will then be resampled by the voxel size scale.

Voxel Size Scale

A scale factor to change the size of the voxels in the resampled volume. 2 will double the voxel size, so result in half the resolution, and one eighth the total voxels.

Flame Density

Scales the flame volume by this and does a maximum of this with density. This is required for smokeless regions that otherwise may be skipped by the renderer. To get a truly zero alpha channel, the smoke density can be set to 0.


Vector VDBs

Names of VDBs to transform as vector volumes. All volumes that match the foo.x, foo.y and foo.z will be merged into single 3-tuple VDBs. If the name matches this list, they will also be flagged as vector-type so they will transform. This ensures velocity vectors transform but avoid having color transforming. This is a space-separated list and can include wildcards.

Cull Mask Volume

When Cull Volume is enabled, this volume specifies the active region to retain. That is, voxels that are outside the active region of Cull Mask Volume will be deactivated.

Density Volume

The name of the density volume used for rendering. This volume is modified when Flame Density is enabled.

Flame Volume

Name of the flame volume used for rendering emission. When Flame Density is enabled, the Density Volume will be updated to capture the presence of flames.

Geometry nodes