A friend of mine was wondering about how to attach per particle expressions to particles via mel
so I wrote this script
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | global proc int doesPPVectorAttrExist( string $attrName, string $particleShape) { //We check to see if the PP attribute is here string $allPPVectors[] = `particle -q -perParticleVector $particleShape`; for ($i in $allPPVectors) { if ($i == $attrName) { return 1; } } return 0; } global proc string myFancyParticles( string $inputShapeNode, string $particleSystemName) { string $returnValue = "Success"; string $namesOfShapeNodes[] = `ls $inputShapeNode`; if (size($namesOfShapeNodes) > 0) { //Create a new particle system using the name entered into the function, use the first occurance inputShapeNode as the emmitter string $newParticles[] = `particle -n ($particleSystemName) -sn ($namesOfShapeNodes[0])`; //this returns an array, first entry is the transform, second is the shape node string $particleTransform = $newParticles[0]; //the shape node may already exist multiple times, so using ls we get the all of them string $allParticleShapes[] = `ls $newParticles[1]`; int $lastEntry = size($allParticleShapes) - 1; //this is a trick to get the length of the array string $currentParticleShape = $allParticleShapes[$lastEntry]; //now we have the lastEntry in the array if (doesPPVectorAttrExist("rgbPP",$currentParticleShape)//See procedure above) { //If the Per particle attribute exists our work is done print "rgbPP found!!!"; } else { //Because the Per Particle Attribute Doesnt exist, we have to make ie print "No rgbPP here!!!, Lets add it!\n"; //Adding a attribute is pretty straight forward addAttr -ln rgbPP -dt vectorArray $currentParticleShape; //Initialise the array to white setParticleAttr -at rgbPP -vv 1 1 1 $currentParticleShape; if (doesPPVectorAttrExist("rgbPP",$currentParticleShape)) { print "rgbPP added all is well!!!\n"; } } //Now bang on the particle expression! as a runtime before dynamics dynExpression -rbd -s "rgbPP = rgbPP * .9;" $currentParticleShape; } else { $returnValue = "Failure"; } return $returnValue; } |
So if you want to test it out
Save it to a location like
/home/samh/exampleScriptingParticles.mel
Then you can try it out with the follow mel snippet in the script window
1 2 3 4 | source "/home/samh/exampleScriptingParticles.mel"; //Update the script file -f -new; //Emptry file polySphere; //Create pSphereShape1 myFancyParticles( "pSphereShape1", "dustSphere"); //Call the function |
