rSSI(r, n, win = owin(c(0,1),c(0,1)), giveup = 1000, x.init=NULL)"owin"
    or something acceptable to as.owin."ppp")."ppp").win.  Starting with an empty window (or with the point pattern x.init
  if specified), the algorithm adds points
  one-by-one. Each new point is generated uniformly in the window
  and independently of preceding points. If the new point lies
  closer than r units from an existing point, then it is rejected
  and another random point is generated.
  The algorithm terminates either when the desired number n
  of points is reached, or when the current point configuration
  has not changed for giveup iterations.
rpoispp,
rMaternI,
rMaternII.