Triple Switch!

That's gonna be the title for my new movie. . . Or the managerial move I make that loses my kid the little league championship game. . . Or a utility node in Maya.
The triple switch is such a weird node. . . Not sure I've ever seen anyone use it in production. But in certain circumstances it can be useful and on rare occasions can be very handy indeed.
Basically the idea of the node is that you can create a geometry-specific attribute of a single material. So, fer example, you could put one shader on 100 objects and have, say, the color be different for each object. Still using just one shader, mind you. . . the color is different for each object, but all the other attrs of the shaders behave as normal. Here's the vid about how that works.

Maya: Using the Triple Switch utility node from zeth willie on Vimeo.


It's kind of hard to imagine getting the most out of this node without some coding, since by definition the node becomes more useful the more stuff (and therefore connections) you have in your scene. . . Here's the code I used to set up the basic random color thingy from the video. To use it, hook the triple switch up to the material, apply the material shader to the objects. Select the TS, then the objects and run the code. Obviously, if you want different results (which you should, probably) then adjust whatever parameters and values you'd like:

//triple switch should already be created and connected to shader

//select triple then objects

string $sel[] = `ls -sl`;

int $sizeObj = size($sel);

string $triple = $sel[0];



for ($i=1; $i<$sizeObj; $i++) {

    string $me = $sel[$i];

    select -r $me;



    //these are the per object attrs we're adding

    addAttr -at "float" -k 1 -ln "redMult";

    addAttr -at "float" -k 1 -ln "greenMult";

    addAttr -at "float" -k 1 -ln "blueMult";



    //these are the random values for those attrs

    float $rRand = `rand .75 1.25`;

    float $gRand = `rand .75 1.25`;

    float $bRand = `rand .75 1.25`;



    //assign the values to the attrs

    setAttr ($me + ".redMult") $rRand;

    setAttr ($me + ".greenMult") $gRand;

    setAttr ($me + ".blueMult") $bRand;



    //connect the objects to the TS

    string $child[] = `listRelatives -c $me`;

    string $shape = $child[0];

    string $meShape = ($shape + ".instObjGroups[0]");



    connectAttr ($meShape) ($triple+".input["+($i-1)+"].inShape");



    //connect the attrs to the TS at the same index the obj is connected

    connectAttr ($me + ".redMult") ($triple+".input["+($i-1)+"].inComp1");

    connectAttr ($me + ".greenMult") ($triple+".input["+($i-1)+"].inComp2");

    connectAttr ($me + ".blueMult") ($triple+".input["+($i-1)+"].inComp3");

    }



}

EDIT: Here's the code I used to create the distance setup. Seems a bit wonky to do things this way, but it more or less works . . . The point here being that since you can use an attr to drive the triple switch, you can control that attr with any of the usual (or unusual means) you control attrs in Maya. For this one you'll need to create a ".tightenFalloff" attr on the measure object first. (BTW, you actually don't need to drive an attr with the distance numbers, you could just plug them into the triple switch directly, but that's a little mysterious for anyone who might use this. The point, again, was simply to illustrate that you don't need colors to drive the triple switch):

///////////////////////

//color by distance

//////////////////////

{

//triple switch should already be created and connected to shader

//select triple then measure object, then textured objects

string $sel[] = `ls -sl`;

int $sizeObj = size($sel);

string $triple = $sel[0];

string $mObject = $sel[1];



for ($i=2; $i<$sizeObj; $i++) {

    string $me = $sel[$i];

    string $meDist = $me + "Distance";

    select -r $me;

    addAttr -at "float" -min 0 -max 1 -k 1 -ln "distance";

   

    //create distance node

    shadingNode -asUtility distanceBetween -n $meDist;

    connectAttr ($me + ".worldMatrix") ($meDist + ".inMatrix1");

    connectAttr ($mObject + ".worldMatrix") ($meDist + ".inMatrix2");

    connectAttr ($me + ".rotatePivotTranslate") ($meDist + ".point1");

    connectAttr ($mObject + ".rotatePivotTranslate") ($meDist + ".point2");

   

    //connect the distance to a mult node

    shadingNode -asUtility multiplyDivide -n ($me+"mult");

    connectAttr ($mObject+".tightenFalloff") (($me+"mult")+".input1X");   

    connectAttr ($meDist+".distance") (($me+"mult")+".input2X");

   

    //connect the dist node to the attr on the object

    connectAttr (($me+"mult")+".outputX") ($me+".distance");



    string $child[] = `listRelatives -c $me`;

    string $shape = $child[0];

    string $meShape = ($shape + ".instObjGroups[0]");



    connectAttr ($meShape) ($triple+".input["+($i-2)+"].inShape");



    connectAttr ($me + ".distance") ($triple+".input["+($i-2)+"].inComp1");

    connectAttr ($me + ".distance") ($triple+".input["+($i-2)+"].inComp2");

    connectAttr ($me + ".distance") ($triple+".input["+($i-2)+"].inComp3");

    }



}