import maya.OpenMaya as om

sgNodeList = om.MSelectionList()
iter_temp = om.MItDependencyNodes(om.MFn.kShadingEngine)

while not iter_temp.isDone():
    sgname = om.MFnDependencyNode(iter_temp.item()).name()
    if (sgname != 'initialShadingGroup')and(sgname != 'initialParticleSE'):
        sgNodeList.add(iter_temp.item())
    iter_temp.next()

om.MGlobal.setActiveSelectionList(sgNodeList)
om.MFileIO.exportSelected('D:/shadingGroup.mb','mayaBinary')

选中a b两物体 判断是否穿插 若穿插则选出a穿入b里的点

import maya.OpenMaya as om
import maya.cmds as mc

sel = om.MSelectionList()
om.MGlobal.getActiveSelectionList(sel)

sourceObj = om.MObject()
targetObj = om.MObject()
targetObjPath = om.MDagPath()
sel.getDependNode(0,sourceObj)
sel.getDependNode(1,targetObj)
sel.getDagPath(1,targetObjPath)
sourceObjDag = om.MFnDagNode(sourceObj)
targetObjDag = om.MFnDagNode(targetObj)
sourceName = sourceObjDag.name()
sourceShape = sourceObjDag.child(0)
targetShape = targetObjDag.child(0)
sourceMesh = om.MFnMesh(sourceShape)
targetMesh = om.MFnMesh(targetObjPath)

hitFaceptr = om.MIntArray()
hitTriptr = om.MIntArray()
hitPointIdList = []

sourceIter = om.MItMeshVertex(sourceShape)
while not sourceIter.isDone():
    hitPoints = om.MFloatPointArray()
    vertexNormal = om.MVector()
    sourceIter.getNormal(vertexNormal)
    vertexNormal *= -1
    vertexNormalF = om.MFloatVector(vertexNormal)
    
    tempMPoint = om.MFloatPoint(sourceIter.position())
    hitpointId = sourceIter.index()
    hit = targetMesh.allIntersections(tempMPoint,vertexNormalF,None,None,True,om.MSpace.kWorld,999,True,None,True,hitPoints,None,hitFaceptr,hitTriptr,None,None)
    if hit:
        if contrastNum(hitPoints[0],hitPoints[1],tempMPoint):
            hitPointIdList.append(hitpointId)

    sourceIter.next()

if len(hitPointIdList)==0:
    print '所选物体没有穿插' 
else:
    mc.select(cl=True)    
    for i in hitPointIdList:
        mc.select(sourceName+'.vtx['+str(i)+']',add=True)


def contrastNum(i,j,k):
    
    if (i.x>k.x>j.x or i.x<k.x<j.x) and (i.y>k.y>j.y or i.y<k.y<j.y) and (i.z>k.z>j.z or i.z<k.z<j.z):
        return True


del hitPointIdList
sel.clear()