Exporting .pc2 files straight out of maya... optimized

# originally from http://www.losart3d.com/?p=559

import maya.cmds as cmds
import struct, os, os.path
import maya.OpenMaya as om

def frange(x, y, jump,):
    ar =[]
    while x < y:
        ar.append(x)
        x += jump
    return ar


def getDagPathFromShape(shape):
    # add the shape to an empty selection list
    sel = om.MSelectionList()
    sel.add(shape)

    # get the dagPath
    dagPathToMesh = om.MDagPath()
    sel.getDagPath( 0, dagPathToMesh )

    # make sure the path is to the shape node (not the transform)
    dagPathToMesh.extendToShape()

    return dagPathToMesh


def getPointList( dagPath ):
    shapeDagPath = getDagPathFromShape(dagPath)

    # create empty point array
    inMeshMPointArray = om.MPointArray()

    # create function set and get points in world space
    currentInMeshMFnMesh = om.MFnMesh(shapeDagPath)
    currentInMeshMFnMesh.getPoints(inMeshMPointArray, om.MSpace.kWorld)

    # put each point to a list
    pointList = []

    for i in range( inMeshMPointArray.length() ) :
        pointList.append( [inMeshMPointArray[i][0], inMeshMPointArray[i][1], inMeshMPointArray[i][2]] )

    return pointList


def writePC2File(filename, shape, world=True, zUp=False, startF=0, endF=100, samplesPerFrame=1):
    sampleRate = 1.0/samplesPerFrame

    dagPath = getDagPathFromShape(shape)
    pointList = getPointList(dagPath)
    numPoints = len(pointList)

    totalFrames = endF - startF
    timeRange = frange(startF, startF+totalFrames+sampleRate, sampleRate)
    numSamples = len(timeRange)

    headerFormat='<12ciiffi'
    headerStr = struct.pack(headerFormat, 'P','O','I','N','T','C','A','C','H','E','2','\0', 1, numPoints, startF, sampleRate, numSamples)

    file = open(filename, "wb")
    file.write(headerStr)

    cmds.refresh(su=True)
    sampleFrames = []

    print "startF=%s endF=%s sampleRate=%s shape=%s" % (startF, startF+numSamples, sampleRate,shape)

    for i in timeRange:
        cmds.currentTime(i)
        pointList = getPointList(dagPath)
        for vPos in pointList:
            vFormat = "fff"
            thisVertex = struct.pack(vFormat, vPos[0], vPos[1], vPos[2])
            file.write(thisVertex)

    cmds.refresh(su=False)
    file.flush()
    file.close()
    print filename," was sucessfully written out"
    return True

'''
#example
out = r'C:\testMaya\test.pc2'
shp = cmds.listRelatives(shapes=True)
writePC2File(out,shp[0],startF=1000,endF=1200,samplesPerFrame=2)
'''