动画表达式算法的问题（物理或数学高手请进）

动画表达式算法的问题（物理或数学高手请进）
这是一段MAYA中的动画表达式,如果您不会MAYA也没关系,相信只要你有程序基础和一定的物理或数学知识,就能回答如下问题.
谁能告诉我这段表达式算法的含义,,（注：我表达式语法没有问题,只解释算法就可以了,只给链接不给解释的混分族勿扰!）
// keep seat balanced
$seatHeight = unicycle:wheel.translateY + 0;
$seatX = unicycle:uniCycle.translateZ;
$wheelX = unicycle:wheel.translateZ;
$dist = abs(unicycle:wheel.translateZ - unicycle:uniCycle.translateZ);
if ($dist = 0)
unicycle:uniCycle.translateY = $seatHeight - $dist/3;
else
unicycle:uniCycle.translateY = $seatHeight;
// Rotation stuff
// global vector $twistold;
vector $twistpos =;
vector $spaz = $twistpos - ;
unicycle:wheel.twistoldX = $twistpos.x;
unicycle:wheel.twistoldY = $twistpos.y;
unicycle:wheel.twistoldZ = $twistpos.z;
//float $rad = wheel.scaleX;
float $rad = .035;
if ($spaz.z {
unicycle:wheel.rotateX = unicycle:wheel.rotateX - mag($spaz)/$rad;
}
if ($spaz.z > 0)
{
unicycle:wheel.rotateX = unicycle:wheel.rotateX + mag($spaz)/$rad;
}
float $dt = 1.0 / 24.0;
float $d;
float $w = 0.0;
$w = $w * $w * $w;
float $a = 0.0;
if( frame == 1 )
{
unicycle:wheel.translateZ = (unicycle:uniCycle.translateZ + unicycle:wheel.translateZTouniCycle_translateZOffset );
}
$d = unicycle:uniCycle.translateZ + unicycle:wheel.translateZTouniCycle_translateZOffset - unicycle:wheel.translateZ;
$w = unicycle:wheel.translateZTouniCycle_translateZWeight; $w = $w * $w * $w;
$a = $w * ( ( $d / $dt ) - unicycle:wheel.translateZ_Velocity ) / $dt;
unicycle:wheel.translateZ_Velocity = unicycle:wheel.translateZ_Velocity + $a * $dt;
unicycle:wheel.translateZ = unicycle:wheel.translateZ + unicycle:wheel.translateZ_Velocity * $dt;
简要说明一下,unicycle:uniCycle是一个独轮自行车的坐架,unicycle:wheel是它的*.