Random

Random distribution

1. Add to each point random points in a circle

   vex

   vector points[]; // not really necessary
   
   for (int i = 0; i < chi("pnum"); i++)
   {
       vector2 v2 = rand(@P.x + i, @P.z + i);
       vector2 in_circle = sample_circle_uniform(v2);
       in_circle *= 0.2;
       vector in_circle_v3 = set(in_circle.x + @P.x, @P.y, in_circle.y + @P.z);
       push(points, in_circle_v3); // umm
       addpoint(0, in_circle_v3);
   }

2. Add points around a point and align to normal

   vex

   vector normal = normalize(@P);
   vector up = {0,1,0};
   matrix3 m = maketransform(normal, up);
   vector4 orient = quaternion(m);
   for (int i = 0; i < chi("pnum"); i++)
   {
       vector2 v2 = rand(@P.x + i, @P.z + i);
       vector2 in_circle = sample_circle_uniform(v2);
       in_circle *= chf("range");
       //The points aligned to the z axis, and up as 0,1,0
       vector in_circle_v3 = set(in_circle.x, in_circle.y, 0); // Important
       in_circle_v3 = qrotate(orient, in_circle_v3);
       in_circle_v3 += @P;
       addpoint(0, in_circle_v3);
   }

Random int from number of points

vex

// Detail mode
int numPts = npoints(0);
float randValue = rand(numPts + @Frame);
float fitFloat = fit(randValue, 0, 1, 0, poolNumPts -1);
int indexSelection = int(fitFloat);

Random samples in cone direction

vex

// run over one point, from add_point SOP
float dist_m = chf("distance");
float angle_d = chf("angle_deg");
float inrshell = chf("inner_shell_dist");
int seed = @ptnum + chi("seed");

vector dir = {0,1,0};
vector rand_len = random(@ptnum);

vector sample_p = sample_direction_cone(
    dir,
    radians(angle_d),
    rand(seed));

float low =  fit01(rand_len.x, inrshell, 1.0);
sample_p *=  low;

@P = sample_p * dist_m;