Voxyde shows how to compute a gradient field from smoke in Houdini.
This new tutorial from Voxyde (Ciobanu Razvan) shows how to use Houdini’s Volume Analysis SOP to compute a gradient field from a smoke simulation.
The tutorial then shows how to use the gradient volume to “squeeze” the particles for a more exciting look.
This tutorial excerpt is from a premium course called advanced particles in Houdini. Check those out here.