原文作者：伍沁憬
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原理：
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MAYA粒子表达式：
int $m = 18;
float $n1 = -15;
float $n2 = 15;
float $n3 = 10;
float $b = 15;
float $a = 8;
float $pi = deg_to_rad(360);
float $min = -5;
float $max = 5;
float $deg = particleShape1.particleId*0.001;
float $mo = ( particleShape1.particleIdP0 )/500;
float $hm = ( particleShape1.particleIdP0)/500;
float $r =10 * pow(pow(abs(cos($m*$deg/4)/($a+$mo)),$n2)+pow(abs(sin($m*$deg/4)*time/($b+$mo*100)),$n3),-1/$n1);
float $height_ratio = 0.5*(1-linstep($min,$max,time*$hm*0.02));
particleShape1.position = <<sin($deg)*$r*$height_ratio,time*$hm*0.02,cos($deg)*$r*$height_ratio>>;
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