Select polygon strip objects ends

select_polystrip_ends.py

import maya.OpenMaya as om
import maya.cmds as cmds
def edgeCapSelector():
    # Check if vertices or faces were selected. 
    # If True convert selection to edges.
    verts = cmds.filterExpand(sm = 31, ex = True, fullPath = True)
    faces = cmds.filterExpand(sm = 31, ex = True, fullPath = True)
    if verts is not None or faces is not None:
        cmds.ConvertSelectionToEdges()
    # Create variable of special class MScriptUtil.
    # It's required to store pointer to integer variable.   
    mutil = om.MScriptUtil()
    # Create variable "resultSelection" of type MSelectionList to store cap edges.
    resultSelection = om.MSelectionList()
    # Create variable "selection" to store current selection.
    selection = om.MSelectionList()
    # Fill "selection" with list of selected objects.
    om.MGlobal.getActiveSelectionList(selection)
    # Create iterator through list of selected objects.
    selection_iter = om.MItSelectionList(selection)
    # Creatre variable to store DagPath to selected object
    selection_DagPath = om.MDagPath()
    # Create variable to store iterating edge as MObject.
    component_edge = om.MObject()
    # Create variable to store pointer to interger value.
    # There is no other way to get to Python value from Maya API function which return &int 
    int_Ptr = mutil.asIntPtr()
    # Variable to store currently iterating object as MObject.
    selectedMObject = om.MObject()
    # Main loop of selection iterator.
    while not selection_iter.isDone():
        # Get list of selected edges (if components are selected, but not object)
        selection_iter.getDagPath(selection_DagPath, component_edge)
        if selection_iter.hasComponents():
            # Create iterator through SELECTED edges, if edges are in selection.
            edge_iter = om.MItMeshEdge(selection_DagPath, component_edge)
        else:
            # Create iterator through ALL edges of currently iterating selected object,
            # becouse object is selected, but not components.
            selection_iter.getDependNode(selectedMObject)
            edge_iter = om.MItMeshEdge(selectedMObject)
        # Main loop of edges iterator
        while not edge_iter.isDone():
            # get pointer to int with number of edges connected to currently iterating 
            edge_iter.numConnectedEdges(int_Ptr)
            # get value from int pointer
            numConEdges = mutil.getInt(int_Ptr)
            # check if it's really polystripe
            if numConEdges != 2 and numConEdges !=4 and numConEdges != 3:
                print edge_iter.index()
                cmds.error('Topology error. Check mesh topology.')
            # if current edge is connected to two edges it's cap edge 
            if numConEdges == 2:
                # add cap edge to MSelectionList where we store results
                resultSelection.add(selection_DagPath, edge_iter.currentItem())
            # get next edge and go to loop begginning 
            edge_iter.next()
        selection_iter.next()

    # if we found cap edges select and highlight them. We highlight them because
    # usually selection is also highlighted in maya, so it looks more natural 
    # for user.    
    if resultSelection.length() > 0:
        om.MGlobal.setSelectionMode(om.MGlobal.kSelectComponentMode)
        om.MGlobal.setHiliteList(selection)
        om.MGlobal.setActiveSelectionList(resultSelection)

edgeCapSelector()