Hi,everyone, I finally surrendered ,I try to do some DLA simulation ,everything goes all right until finally I tried to skeletion it(i.e.connect each particle by line to shape the whole pattern,maybe can be done via point cloud in VOPs to find the direction between colliding particle and target one and connect in SOPs,but I failed to do it ) could any one here enlighten me a bit,thanks very much in advance. here is my basic DLA sim,for DLA System see http://en.wikipedia.org/wiki/Diffusion-