float $radius = 20;
float $pi = 3.141592;

float $theta = rand(1);
float $theta2 = $pi*2 * rand(1) ;

float $y = cos($theta2) * $radius;
float $x = sin($theta *$pi*2 ) * sin($theta2) * $radius;
float $z = cos($theta* $pi*2 ) * sin($theta2) * $radius;

particleShape1.position = <<$x,$y,$z>>;