Brian Escribano - MEL & Python Tricks

Python: curveOffset

nospam@example.com (Brian Escribano) — Tue, 27 May 2008 21:54:00 -0600

Was challenged two weeks to write a script that selects all odd or even CVs of a nurbs curve. Kind of a speed challenge, but was distracted during the writing of the script so what should of taken less then 10 minutes to write turned into 20 minutes.

#Created by Brian Escribano, www.meljunky.com import maya.cmds as cmds def curveOffset( ): selection = cmds.ls(selection=True) curve = selection[0].split('.')[0] selCV = selection[0][ selection[0].find('[')+1 : selection[0].find(']') ] numSpans = cmds.getAttr( curve + '.spans' ) degree = cmds.getAttr( curve + '.degree' ) form = cmds.getAttr( curve + '.form') numCVs = numSpans + degree; if ( form == 2 ): numCVs -= degree try: state = int(selCV) % 2 except: state = 0 selCV = numCVs + 1 if state == 0: selList = range(0, numCVs-1, 2) # evens else: selList = range(1, numCVs, 2) # odds for sel in selList: if sel != int(selCV): cmds.select( curve + '.cv[' + str(sel) + ']', toggle=True)

Python: parentCurve

nospam@example.com (Brian Escribano) — Tue, 27 May 2008 21:51:56 -0600

parentCurve function allows for quick parenting of nurbs curve's shape node to a given list or selection.

Keyword Arguments:
normal=(1,0,0) #Sets the normal direction of the makeNurbsCurve, default to X
radius=0.5 #Adjust the radius of the curve
color=None #Change the color of the curve, choices are [1-31]
selList=None #The list of nodes to make the adjustments. Default will be the current selection

#Created by Brian Escribano, www.meljunky.com 
import maya.cmds as cmds
def parentCurve(normal=(1,0,0), radius=0.5, color=None, selList=None):
    circleList = []
    if not selList:
        selList = cmds.ls(selection=True)
    for node in selList:
        circle = cmds.circle(c=[0, 0, 0],nr=[0, 1, 0], sw=360, r=1, d=3, ut=0, tol=0.01, s=8, ch=1)
        shapes = cmds.listRelatives(circle[0], shapes=True)
        cmds.parent(circle[0], node)
        cmds.makeIdentity(circle[0], apply=False, t=1, r=1, s=1, n=0)
        cmds.parent(shapes[0], node, r=1, s=1)
        cmds.delete(circle[0])        
        cmds.setAttr( circle[1] + '.normalX', normal[0] )
        cmds.setAttr( circle[1] + '.normalY', normal[1] )
        cmds.setAttr( circle[1] + '.normalZ', normal[2] )
        cmds.setAttr( circle[1] + '.radius', radius )
        if color:
            cmds.setAttr( shapes[0] + '.overrideEnabled', 1)
            cmds.setAttr( shapes[0] + '.overrideColor', color )
        circleList.append( shapes[0] )
    return circleList

Python: groupAbove

nospam@example.com (Brian Escribano) — Tue, 27 May 2008 20:29:43 -0600

This short function will create a group node above the nodes in a given list. If no list is provided then the selection is used. Has the ability for search and replace. The group node will be placed in the same position, to zero out the controls of translation and rotation. Will also adjust the parenting as needed.

#Created by Brian Escribano, www.meljunky.com 
import maya.cmds as cmds
def groupAbove( search, replace, selList=None ):
    #Grab current selection
    if not selList:
        selList = cmds.ls(selection=True)
    for node in selList:
        groupName = node.replace(search, replace)
        group = cmds.group(world=True, empty=True, name=groupName)
        cmds.parent(group, node)
        cmds.makeIdentity(group, apply=False, t=1, r=1, s=1, n=0)
        cmds.parent(group, w=True)
    
        #determine parent
        parents = cmds.listRelatives(node, parent=True)
        if parents != None:
            cmds.parent(group, parents[0])
        cmds.parent(node, group)

For example: groupAbove('CTRL', 'GRP') will create a group node with the named change by the search and replace keyword.

One limitation of MEL over Python is the inability to setup default keyword arguments in functions (procedures). For MEL to create reusability for a procedure to work with a selection or a custom array will take multiple commands or procedure.

Continue reading "Python: groupAbove"

Arguments return values using MEL

nospam@example.com (Brian Escribano) — Fri, 07 Mar 2008 11:39:05 -0700

In Python when the following is executed:

import maya.OpenMaya as OpenMaya
selection = OpenMaya.MSelectionList()
OpenMaya.MGlobal.getActiveSelectionList( selection )

An instance of the class MSelectionList is created and is called 'selection'. The empty 'selection' is passed to the funtion getActiveSelectionList of the class MGlobal which populates 'selection' with the active selection list.

The following example will use MEL to pass an empty array to a procedure which in turn will populate it. Without using a return statement.

proc addColor(string $result[]){
string $colorList[] = {"Cyan", "Yellow", "Magenta", "Black"};
for ( $color in $colorList){
$result[size($result)] = $color;
}
}

string $ink[] = {};
addColor( $ink );
print $ink;

The results of $ink is:
Cyan
Yellow
Magenta
Black

Don't have to use a loop to return the results. Setting $colorList to $result will do the same thing. Wanted to show that something can be done to the array before the results are "returned".

Convert Dynamic

nospam@example.com (Brian Escribano) — Mon, 15 Oct 2007 21:08:07 -0600

Copies the translation and rotation to a new object. Useful for converting dynamic object tranformation to keyframe. Will need to "Simplify Curve" since their will be keyframes on X number of frames.

/* convertDynamic Copies the translation and rotation to a new object. Useful for converting dynamic object tranformation to keyframe. Will need to "Simplify Curve" since their will be keyframes on X number of frames. Accepts 5 arguements: string $dynObj - Dynamic object string $newObj - New object that will be keyframe int $startFrame - Start keyframe int $endFrame - End Keyframe int $byFrame - Increment frame by x value. 1 will equal every frame Sample: convertDynamic ("nurbsSphere1", "nurbsSphere2", 1, 480, 20); Created by Brian Escribano Website: www.melJunky.com Email: brian@meljunky.com Version 1.0: October 15, 2007 */ global proc convertDynamic (string $dynObj, string $newObj, int $startFrame, int $endFrame, int $byFrame){ float $translate[], $rotate[]; for ($frame=$startFrame ;$frame<=$endFrame; $frame += $byFrame){ currentTime $frame; $translate = `getAttr ($dynObj + ".t")`; $rotate = `getAttr ($dynObj + ".r")`; xform -t $translate[0] $translate[1] $translate[2] $newObj; xform -ro $rotate[0] $rotate[1] $rotate[2] $newObj; setKeyframe -at translate $newObj; setKeyframe -at rotate $newObj; } } }

Download MEL Script: dynToKeyframe.mel

Welcome to MELTricks

nospam@example.com (Brian Escribano) — Mon, 27 Aug 2007 11:54:05 -0600

Tips and Tricks that did not find their way into my scripts.. or had they? The formatted code will be perserved if you copy text from the field. The MEL file is available for download.

Custom PickWalk

nospam@example.com (Brian Escribano) — Sat, 25 Aug 2007 09:53:45 -0600

The script allows pick walking based off an array using hot keys that the user will define. The hotkeys will call the procedure pickWalk2("up") to move up in the array or pickWalk2("down") to move down the aray. Change the array to the order of controls that you want selected when the custom pickwalk is enabled.

global proc pickWalk2 (string $walk){ int $j; string $pickWalk[] = {"circle1CTRL", "circle2CTRL", "circle3CTRL", "circle4CTRL" }; string $sel[] = `ls -sl`; $count = stringArrayCount($sel[0], $pickWalk); if ($count > 0){ for ($i=0; $i < size($pickWalk); $i++){ if ($sel[0] == $pickWalk[$i]){ if ($walk == "up"){ $j = $i + 1; if ($j == size($pickWalk)) $j = 0; select $pickWalk[$j]; break; }//end if up else{ $j = $i - 1; if ($j == -1) $j = `size($pickWalk)`-1; select $pickWalk[$j]; break; }//end else }//end if }//end for }//end if }//end global proc

Download MEL Script: pickWalk.mel

Stretchy IK

nospam@example.com (Brian Escribano) — Sat, 25 Aug 2007 09:51:13 -0600

The script creates a node based stretchy IK system based of the distance of the children distance from its parent. That means the joint will lock straight before the stretch begins.

/* ikStretch Create a node based ik stretch for joint chains Accepts 3 arguements: $rootJnt - root joint of ik chain $ctrl - The control object that transform the ik handle $prefix - prefix used to describe the type of chain i.e. lf_arm Created by Brian Escribano Website: www.melJunky.com Email: brian@meljunky.com Version 1.0: June 3, 2006 */ global proc ikStretch (string $rootJnt, string $ctrl, string $prefix){ //Determine Children string $midJnt[] = `listRelatives -type joint $rootJnt`; string $endJnt[] = `listRelatives -type joint $midJnt`; //Create and parent group nodes string $aimGrp = `group -em -n ($prefix + "_distAim_ikGRP") -p $rootJnt`; //temp parent to move group to rootJnt string $pntGrp = `group -em -n ($prefix + "_distPnt_ikGRP") -p $aimGrp`; //Aim/point constraint the aimGrp/pntGrp to the ctrl aimConstraint -offset 0 0 0 -weight 1 -aimVector 1 0 0 -upVector 0 1 0 -worldUpType "vector" -worldUpVector 0 1 0 $ctrl $aimGrp; pointConstraint -offset 0 0 0 -weight 1 $ctrl $pntGrp; //get distance of pntGrp, min and end //float $pntGrpDist = `getAttr ($pntGrp + ".translateX")`; float $midJntDist = `getAttr ($midJnt[0] + ".translateX")`; float $endJntDist = `getAttr ($endJnt[0] + ".translateX")`; float $distance = abs($midJntDist) + abs($endJntDist); //creaye multiply divide node string $mdNode = `createNode -n ($prefix + "_mp_UTL") multiplyDivide`; setAttr ($mdNode + ".operation") 2; connectAttr -f ($pntGrp + ".translateX") ($mdNode + ".input1X"); setAttr ($mdNode + ".input2X") $distance; //create condition string $cnNode = `createNode -n ($prefix + "_cn_UTL") condition`; setAttr ($cnNode + ".operation") 3; setAttr ($cnNode + ".secondTerm") 1; connectAttr -f ($mdNode + ".outputX") ($cnNode + ".firstTerm"); connectAttr -f ($mdNode + ".outputX") ($cnNode + ".colorIfTrueR"); //connect scale connectAttr -f ($cnNode + ".outColorR") ($rootJnt + ".scaleX"); connectAttr -f ($cnNode + ".outColorR") ($midJnt[0] + ".scaleX"); //parent aimGrp to a pad node to preserve translation on aimGrp when parenting string $stretchGrp = `group -em -w -n ($prefix + "_stretch_ikGRP")`; parent $aimGrp $stretchGrp; }

Download MEL Script: ikStretch.mel

Stretchy Back IK

nospam@example.com (Brian Escribano) — Sat, 25 Aug 2007 09:49:06 -0600

The script creates a node based stretchy back IK system based of the distance of the curveInfo node. If you did not create one, one will be provided.

/* ikBackStretch Create a node based ik back stretch for joint chains. If no curveInfo is created script will generate one Accepts 3 arguements: $jnts[] - list of joints can be `ls -sl` when calling procedure while joints selected $curve[] - name of curve for ik spline $type - 1 min stretch is equal to 1 !1 (non one value, like 0) Stretch can go below 1 Created by Brian Escribano Website: www.melJunky.com Email: brian@meljunky.com Version 1.0: June 4, 2006 */ global proc ikBackStretch (string $jnts[], string $curve, int $type) { float $crvDistance; string $eval; //determin if their is a curve info node already exists string $curveShape[] = `listRelatives -s $curve`; string $curveInfo[] = `listConnections -t curveInfo $curveShape[0]`; if (size($curveInfo) == 0) $curveInfo[0] = `arclen -ch 1 $curve`; $crvDistance = `getAttr ($curveInfo[0] + ".arcLength")`; string $mdNode = `createNode -n ($curve + "_mp_UTL") multiplyDivide`; setAttr ($mdNode + ".operation") 2; connectAttr -f ($curveInfo[0] + ".arcLength") ($mdNode + ".input1X"); setAttr ($mdNode + ".input2X") $crvDistance; if ($type == 1) { //create condition string $cnNode = `createNode -n ($curve + "_cn_UTL") condition`; setAttr ($cnNode + ".operation") 3; setAttr ($cnNode + ".secondTerm") 1; connectAttr -f ($mdNode + ".outputX") ($cnNode + ".firstTerm"); connectAttr -f ($mdNode + ".outputX") ($cnNode + ".colorIfTrueR"); //connect scale for ($eval in $jnts){ connectAttr -f ($cnNode + ".outColorR") ($eval + ".scaleX"); } } else{ for ($eval in $jnts){ connectAttr -f ($mdNode + ".outputX") ($eval + ".scaleX"); } } }

Download MEL Script: ikBackStretch.mel

Color Override

nospam@example.com (Brian Escribano) — Sat, 25 Aug 2007 09:31:47 -0600

This script allows the coloration of shape and most transform nodes. View the header for more information

/* colorOverride Disconnects the overrideColor from the layer if available and applies the color given Accepts 2 arguements: $list[] - Nodes that will have their color changed. Transform nodes will be evaluated to color a shape node if available. `ls -sl` can be used to color the selection $color - values are based of Colors preference, index 1. (Window -> Settings/Preferences -> Colors...Tab(Active)) examples: 6 blue, 13 Red, 14 Green, 17 Yellow Created by Brian Escribano Website: www.melJunky.com Email: brian@meljunky.com Version 1.0: June 7, 2006 */ //This script is desiged to change the colorover fuction to a given color global proc colorOverride (string $list[], int $color){ string $shape[], $layer[], $colorNode; for ($node in $list){ //determine shape node $shape = `listRelatives -f -s $node`; if (size($shape) == 0){ //transform only $colorNode = $node; }else{ //shape node $colorNode = $shape[0]; } //determine layer $layer = `listConnections -t displayLayer $colorNode`; //disconnect layer if exists if (size($layer) != 0) disconnectAttr ($layer[0] + ".drawInfo") ($colorNode + ".drawOverride"); setAttr ($colorNode + ".overrideEnabled") 1; setAttr ($colorNode + ".overrideColor") $color; } print "Color override complete."; }

Download MEL Script: colorOverride.mel

multiDriverSDK

nospam@example.com (Brian Escribano) — Fri, 24 Aug 2007 12:12:00 -0600

This script create a network of utilities that will connect two attributes using ethier a multiplyDivide of plusMinusAverage node. The operation can be changed. A Set Driven Key is set up between the output and the driven. The values are change using a float arrays.

/* multiDriverSDK Connects two drivers through a given operation and connects the output to a driven with the given float values Accepts 6 arguements: string $driver1 - name of the first driver and attr. For example "mySphere.tx" string $driver2 - name of the second driver and attr. For example "myCube.tx" string $equation - Type of operation. Avaliable operations are multiply, divide, power, sum, subtract, average float $driverValue[] - float range for the sdk using an array. Can include as many sdk as needed. float $drivenValue[] - Same as above. Need to be the same size array string $driven - name of the first driven and attr. For example "mySphere.tx" Created by Brian Escribano Website: www.melJunky.com Email: brian@meljunky.com Version 1.0: June 12, 2006 */ global proc multiDriverSDK (string $driver1, string $driver2, string $equation, float $driverValue[], float $drivenValue[], string $driven){ string $nodeType, $nodeName, $suffix, $nodeOutput; int $opperation; //Determin node type to create if ($equation == "multiply" || $equation == "divide" || $equation == "power"){ $suffix = "_md_UTL"; $nodeOutput = ".outputX"; if ($equation == "multiply") $opperation = 1; if ($equation == "divide") $opperation = 2; if ($equation == "power") $opperation = 3; $nodeName = `createNode multiplyDivide -name ($driven + $suffix)`; connectAttr -f $driver1 ($nodeName + ".input1X"); connectAttr -f $driver2 ($nodeName + ".input2X"); } if ($equation == "sum" || $equation == "subtract" || $equation == "average"){ $suffix = "_pma_UTL"; $nodeOutput = ".output1D"; if ($equation == "sum") $opperation = 1; if ($equation == "subtract") $opperation = 2; if ($equation == "average") $opperation = 3; $nodeName = `createNode plusMinusAverage -name ($driven + $suffix)`; connectAttr -f $driver1 ($nodeName + ".input1D[0]"); connectAttr -f $driver2 ($nodeName + ".input1D[1]"); } //Set the operation setAttr ($nodeName + " .operation") $opperation; for ($i=0; $i<size($drivenValue); $i++){ setDrivenKeyframe -dv $driverValue[$i] -v $drivenValue[$i] -cd ($nodeName + $nodeOutput) $driven; } //print out that script is complete print ("MultiDriverSDK is complete."); }

Download MEL Script: multiDriversSDK.mel