build_connected_chain.py

import bpy

side_identifier = "_X_"
finger_identifier = "_FingerN"

chainlinks = {}
chainlinks["body"] = ( "ValveBiped.Bip01", "ValveBiped.Bip01_Pelvis", "ValveBiped.Bip01_Spine", "ValveBiped.Bip01_Spine1", "ValveBiped.Bip01_Spine2", "ValveBiped.Bip01_Spine4" )
chainlinks["arms"] = ( "ValveBiped.Bip01_X_Clavicle", "ValveBiped.Bip01_X_UpperArm", "ValveBiped.Bip01_X_Forearm", "ValveBiped.Bip01_X_Hand" )
chainlinks["fingers"] = ( "ValveBiped.Bip01_X_FingerN", "ValveBiped.Bip01_X_FingerN1", "ValveBiped.Bip01_X_FingerN2" )
# TODO: legs, pelvis+neck+head

obj =  bpy.context.selected_objects[0]
bones = obj.data.edit_bones

def this_thing_doesnt_exist(str):
    print( str, "not in hiearchy" )

def make_connected_chaintuple(tuple_obj, side="", fingernum=0):
    tuple_len = len(tuple_obj)
    chainboneslist = []
    for chainbonenum in range(0, tuple_len):
        bonename = tuple_obj[ chainbonenum ]
        bonename = bonename.replace( side_identifier, side ).replace( finger_identifier, "_Finger" + str(fingernum) )
        if bonename in bones:
            chainboneslist.append( bonename )
            print(chainbonenum, tuple_obj[ chainbonenum ], bonename)
        else:
           this_thing_doesnt_exist(bonename)
    print(tuple_obj,chainboneslist)
    list_len = len( chainboneslist )
    for chainbonenum in range(0, list_len-1):
        curbone = bones[ chainboneslist[ chainbonenum ] ]
        nextbone = bones[ chainboneslist[ chainbonenum+1 ] ]
        endpos = nextbone.head
        curbone.tail = endpos
        nextbone.use_connect = True
    curbone = bones[ chainboneslist[ list_len-1 ] ]
    curbone.length = bones[ chainboneslist[ list_len-2 ] ].length
    
        

def make_connected_chain():
    make_connected_chaintuple( chainlinks["body"] )
    for side in ("_L_", "_R_"):
        make_connected_chaintuple( chainlinks["arms"], side )
        for fingernum in range(0,5):
            make_connected_chaintuple( chainlinks["fingers"], side, fingernum )
            
make_connected_chain()