The VDB Filter operator can be used to apply various filtering algorithms to voxels.
Grid names: the names of the source VDB grids.
Filter: controls which filter will be applied to the specified grids.
Explanations for each filter can be found in the online OpenVDB documentation, with the exception of “minify” and “maxify”, which are filters that apply dilation/erosion in equal amounts in order to reduce isolated voxels or fill concave holes in voxels clusters.
Width: the size of the filter (in voxel units).
Iterations: the number of times to apply the filter each time step.