[Frank Verberne]

I think you can just apply a vizproximity sensor with a circlearea of 5 (meters) to one (moving) avatar, and add a vizproximity target to the other (moving) avatar. When the avatars are within 5 meters from each other, the sensor (avatar1) should sense the target (avatar), and then you can respond to that event.

See the example below

import viz
import vizact
import vizshape
import vizproximity

viz.go()

sphere = vizshape.addSphere(radius=1)
sphere.setPosition(0,0,20)
sphere.color(viz.GREEN)

box = viz.add('box.wrl')
box.color(viz.ORANGE)

def moveObjects():
  boxPos = box.getPosition()
  boxPos[2] += .1
  box.setPosition(boxPos)
  spherePos = sphere.getPosition()
  spherePos[2] += .01
  sphere.setPosition(spherePos)

vizact.ontimer(.1, moveObjects)

manager = vizproximity.Manager()

target = vizproximity.Target(sphere)
manager.addTarget(target)
sensor = vizproximity.Sensor( vizproximity.CircleArea(5),source=box)
manager.addSensor(sensor)

def EnterProximity(e):
  print 'enter'

def ExitProximity(e):
  print 'exit'

manager.onEnter(sensor,EnterProximity)
manager.onExit(sensor,ExitProximity)