In POPForces their is a KILL POP (DOPs) and it has a nice feature that confines effect of the KillPOP to a bounding volume or geometrySOP. This is really nice.
Now how can other other fields, forces, and microsolvers be confined to particular volume?
For example POPWind be confined within a sphere, cylinder, or box.
I tried SOP input but that does not appear to work.

Thank you