Radial Force dynamic tool

#
# Produced by:
#       Graham Thompson
#       captainhammy@gmail.com
#       www.captainhammy.com
#
# Name:         dop_radialforce.shelf
#
# Comments:     Creates a radial force that acts on dynamic objects using metaballs.
# 
# Version:      1.0
#
# Compatibility: Houdini 9.0
#
 
import toolutils
import dopgeofiltertoolutils
 
def magnetValidateGeometry(objnode):
    geometry = objnode.displayNode().geometry()
    for prim in geometry.prims():
        if prim.type() == hou.primType.Metaball:
            return
    else:
        msg = "Selected magnet geometry has no metaballs."
        raise hou.OperationFailed(msg)
 
activepane = toolutils.activePane(kwargs)
 
if isinstance(activepane, hou.SceneViewer):
 
    magnet = dopgeofiltertoolutils.genericDopGeoForceTool(activepane, 'magnetforce', magnetValidateGeometry,
                                               "magnetforce__radial1",
                                               "Select the dynamic object(s) to apply the radial force to and press Enter to continue.",
                                                "Select the object to drive the radial force and press Enter to continue.")
 
    magnet.parm("forcescale").set(-10000)
    magnet.setName("radialforce1", True)