Generating Curves from Motion Trails in Maya

In this tutorial, we will learn a technique for creating curves from Editable Motion Trails with the help of Python in Maya. Here's the script: https://www.dropbox.com/s/9wz0dfnrcpvdtu8/motionTrail_to_curve_python.pdf?dl=0

import maya.cmds as mc

'''
Motion Trail to Curve
Instructions: select animated object(s), and run script…
'''
#Find selected transform nodes
sel = mc.ls(sl=True, type='transform')
#Get playback start time
start = mc.playbackOptions(q=True, min=True)
#Get playback end time
end = mc.playbackOptions(q=True, max=True)
#For Loop - iterate on each selected object
for each in sel:
    #Create geometry - used later for a snapshot trail
    geo = mc.polyCube()[0]
    #Point Constrain the geometry to the selected object
    mc.pointConstraint(each, geo)
    #Select the geo we created and create an animated snapshot
    mc.select(geo, r=True)
    #Create variable "snap_node" that stores the snapshot group
    snap_node = mc.snapshot(n=each + '_snap', i=1, st=start, et=end, u='animCurve')
    #Find parented objects stored in snapshot group
    trail_geo = mc.listRelatives(snap_node[0], c=True)
    #Get the amount of objects parented to snapshot group
    size = len(trail_geo)
    #Create Curve
    cv_node = mc.curve(d=1, p=[(0, 0, 0), (0, 0, 1)])
    #Rebuild the curve to create the new curve we will align to our motion trail
    cv = mc.rebuildCurve(cv_node, ch=False, rpo=True, rt=0, end=0, s=size-1, d=1)
    #Select all points on the rebuilt curve
    mc.select((cv[0] + '.cv[0:*]'), r=True)
    #Store component selection in variable "pts"
    pts = mc.ls(sl=True, fl=True)
    #For Loop - iterate using the amount of snapshat geo stored in snapshot group  
    for i in range(size):
        #Select each snapshot geo
        mc.select(trail_geo[i], r=True)
        #Connect a cluster to each snapshot mesh
        cl = mc.cluster()
        #Rename the snapshot clusters
        mc.rename(cl[1], (each + '_' + str(i) + '_cl'))
    #Clear selection
    mc.select(cl=True)
    #For Loop - iterate using the amount of snapshat geo stored in snapshot group
    for i in range(size):
        #Create variable for snapshot clusters
        cl_geo = each + '_' + str(i) + '_cl'
        #Select each curve point and create a cluster
        mc.select(pts[i], r=True)
        cl_pt_node = mc.cluster()
        #Rename curve point clusters
        cl_pt = mc.rename(cl_pt_node[1], (each + '_' + str(i) + '_pt_cl'))
        #Now, align curve clusters to snapshot clusters!
        mc.delete(mc.pointConstraint(cl_geo, cl_pt))
    #Remove initial geometry used for snapshot, and remove snapshot group
    mc.delete(geo, snap_node[0]) 
    #Remove history on curve to bake the cluster deformations
    mc.delete(cv, ch=True)  
    #Finally, make the curve smooth
    mc.rebuildCurve(cv, ch=False, rpo=True, rt=0, end=0, kcp=True, kep=True, d=3)