APF is great but might as well use the VDB tools - not really any extra benefit with APF

APField - select the APField "satellite" operator that corresponds with these settings

PGroup - sets the particle group to be affected by the 3d volume field.

Include Sub Groups - check this option to use the particles in the sub-hierarchy as well.

In From - the field data can be set by many aspects of a particle. The options are:

Velocity - when selected the particle's speed will be used to fill the cell (voxel).

Position - when selected the particle's position will be used to fill the cell (voxel).

Scale - when selected the particle's scale will be used to fill the cell (voxel).

Size - when selected the particle's size will be used to fill the cell (voxel).

Mass - when selected the particle's mass will be used to fill the cell (voxel).

Data Channel - if a data channel exists it can be selected to fill the cell (voxel)

Multiplier - use this multiplier to increase or decrease the value written to the cell (voxel).

Weight DChan. - defines a data channel containing a weighting factor that can be set per particle through a data channel. The higher this value the longer the original value will be kept.

On the APField node, remember that smaller "Dimension" values mean smaller, finer, higher resolution fields.

And within that Dimension, the "Cells per Dim." defines how many cells, so increasing "Cells per Dim." will increase the number of cells.

Currently, one field cannot hold multiple types of values, but you can create many fields and they can all affect the particles (using multiple APFOutputTo operators).