Calculate superficial area and volume of mesh with Three.js(WebGL)

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//Created by Ken on Oct 20,2016 for volume compute when uploadfunction SignedVolumeOfTriangle(p1, p2, p3) {   var v321 = p3.X*p2.Y*p1.Z;   var v231 = p2.X*p3.Y*p1.Z;   var v312 = p3.X*p1.Y*p2.Z;   var v132 = p1.X*p3.Y*p2.Z;   var v213 = p2.X*p1.Y*p3.Z;   var v123 = p1.X*p2.Y*p3.Z;   var singnedVolume=(1/6)*(-v321 + v231 + v312 - v132 - v213 + v123);   return singnedVolume;}function VolumeOfMesh(points) {       var i= 0,vols=0;   var P1,P2,P3;   do   {      P1={X:points[i],Y:points[i+1],Z:points[i+2]};      P2={X:points[i+3],Y:points[i+4],Z:points[i+5]};      P3={X:points[i+6],Y:points[i+7],Z:points[i+8]};      vols+=SignedVolumeOfTriangle(P1, P2, P3);      i+=9;   }   while (i<points.length);   return customRound(Math.abs(vols)/1000,2);}function customRound(number,fractiondigits){   with(Math){      return round(number*pow(10,fractiondigits))/pow(10,fractiondigits);   }}function SuperficialAreaOfMesh(points) {   var _len =points.length,      _area = 0.0;   if (!_len) return 0.0;   var i= 0,vols=0;   var va,vb,vc;   do   {      va={X:points[i],Y:points[i+1],Z:points[i+2]};      vb={X:points[i+3],Y:points[i+4],Z:points[i+5]};      vc={X:points[i+6],Y:points[i+7],Z:points[i+8]};      var ab = {X:vb.X-va.X,Y:vb.Y-va.Y,Z:vb.Z-va.Z};         //vb.clone().sub(va);      var ac = {X:vc.X-va.X,Y:vc.Y-va.Y,Z:va.Z-vc.Z};      //vc.clone().sub(va);      var cross = new THREE.Vector3();      cross=crossVectors( ab, ac );      _area += Math.sqrt(Math.pow(cross.X,2)+Math.pow(cross.Y,2)+Math.pow(cross.Z,2))/2;      i+=9;   }   while (i<points.length);   return customRound(Math.abs(_area)/100,2);} function crossVectors( a, b ) {   var ax = a.X, ay = a.Y, az = a.Z;   var bx = b.X, by = b.Y, bz = b.Z;    var P={X:ay * bz - az * by,          Y:az * bx - ax * bz,          Z:ax * by - ay * bx}   return P;}
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