# Add distance attribute to motion paths.
import maya.cmds as cmds
attr = "distance"
for mp in set(c
    for a in cmds.ls(sl=True)
    for b in [a] + (cmds.listRelatives(a, ad=True) or [])
    for c in cmds.listConnections(b, t="motionPath") or []
    if not cmds.attributeQuery(attr, n=c, ex=True)):
    cmds.addAttr(mp, sn=attr, k=True)
    for length in (cmds.arclen(a, ch=True) for a in cmds.listConnections(mp, type="nurbsCurve") or []):
        clamp, mul = cmds.shadingNode("clamp", au=True), cmds.shadingNode("multiplyDivide", au=True)
        for src in cmds.listConnections("%s.uValue" % mp, p=True, d=False) or []:
            for crv in cmds.ls(cmds.listHistory(src) or [], type="animCurve"):
                cmds.scaleKey(crv, vs=cmds.getAttr("%s.arcLength" % length))
            cmds.connectAttr(src, "%s.%s" % (mp, attr), f=True)
        for dst in cmds.listConnections("%s.uValue" % mp, p=True, s=False) or []:
            cmds.connectAttr("%s.%s" % (mp, attr), dst, f=True)
        cmds.connectAttr("%s.arcLength" % length, "%s.input2X" % mul, f=True)
        cmds.connectAttr("%s.arcLength" % length, "%s.maxR" % clamp, f=True)
        cmds.connectAttr("%s.%s" % (mp, attr), "%s.inputR" % clamp, f=True)
        cmds.connectAttr("%s.outputR" % clamp, "%s.input1X" % mul, f=True)
        cmds.connectAttr("%s.outputX" % mul, "%s.uValue" % mp, f=True)
        cmds.setAttr("%s.operation" % mul, 2)