Spherical Coordinates Tutorial Expression 2

spherical_exp_02.mel

float $rate = 3.14 / 2.0;
float $theta = offset.translateX * $rate + control.translateX * $rate;
float $phi = offset.translateY * $rate - control.translateY * $rate;

float $x = sin($theta) * sin($phi);
float $y = cos($phi);
float $z = cos($theta) * sin($phi); 

float $px = $x / (1 - $z);
float $py = $y / (1 - $z);
$px = $px * 0.5;
$py = $py * 0.5;

$x = (2 * $px) / (1 + pow($px, 2) + pow($py, 2));
$y = (2 * $py) / (1 + pow($px, 2) + pow($py, 2));
$z = (-1 + pow($px, 2) + pow($py, 2)) / (1 + pow($px, 2) + pow($py, 2));

constraint.translateZ = $z;
constraint.translateX = $x;
constraint.translateY = $y;