Maya Python Create joints Hierachy

Question

I'm trying to create o hierarchy of joints for a skeleton in maya python. And I'm doing this

def makeSkelet(args):

    helperSkelet('Root_Locator', 'root_Joint')
    helperSkelet('Pelvis_Locator', 'pelvis_Joint')
    helperSkelet('Spine_Locator', 'spine_Joint')
    helperSkelet('Spine01_Locator', 'spine01_Joint')
    helperSkelet('Spine02_Locator', 'spine02_Joint')
    helperSkelet('Neck_Locator', 'neck_Joint')
    helperSkelet('Head_Locator', 'head_Joint')
    mc.select(cl=True)
    helperSkelet('ArmL_Locator', 'armL_joint')
    helperSkelet('ElbowL_Locator', 'elbowL_Joint')
    helperSkelet('HandL_Locator', 'handL_Joint')
    mc.select(cl=True)
    helperSkelet('ArmR_Locator', 'armR_joint')
    helperSkelet('ElbowR_Locator', 'elbowR_Joint')
    helperSkelet('HandR_Locator', 'handR_Joint')
    mc.select(cl=True)
    helperSkelet('HipL_Locator', 'hipL_joint')
    helperSkelet('KneeL_Locator', 'kneeL_Joint')
    helperSkelet('AnkleL_Locator', 'ankleL_Joint')
    helperSkelet('FootL_Locator', 'footL_Joint')
    mc.select(cl=True)
    helperSkelet('HipR_Locator', 'hipR_joint')
    helperSkelet('KneeR_Locator', 'kneeR_Joint')
    helperSkelet('AnkleR_Locator', 'ankleR_Joint')
    helperSkelet('FootR_Locator', 'footR_Joint')

Now this works fine, because the joints must be created in this order. (the helper skelet is a function where i create the joint with the reference to a locator position)

I was wondering if there is a more optimized way to do this considering the order or creation must be kept .

Thank you

Answer 1

If by "optimize" you mean getting better performace, I agree with what @downshift said.

If what you meant was instead making your code "cleaner" (more general or scalable or simply more pythonic), here's another way you can do the same, which is a bit more compact (and separates the logic from your input):

def helperSkeletGroup(group, symmetric=False):
    # quick workaround to capitalize a word, leaving the following letters unchanged
    capitalize = lambda s: s[:1].upper() + s[1:]

    symmetric_group = []
    for elem in group:
        if symmetric:
            symmetric_group.append('{0}R'.format(elem))
            elem = '{0}L'.format(elem)
        # format locators and joints
        loc, joint = '{0}_Locator'.format(capitalize(elem)), '{0}_Joint'.format(elem)
        helperSkelet(loc, joint)
    cmds.select(cl=True)
    if symmetric_group:
        helperSkeletGroup(symmetric_group)

helperSkeletGroup(['root', 'pelvis', 'spine', 'spine01', 'spine02', 'neck', 'head'])
helperSkeletGroup(['arm', 'elbow', 'hand'], True)
helperSkeletGroup(['hip', 'knee', 'ankle', 'foot'], True)

This comes with a few advantages:

• it handles symmetry for you
• the code doesn't grow too much, as the number of joints increases
• if at some point you want to change the naming convention for locators and joints, you can do it by changing a single line

Alternatively, you could go with an OOP approach. Here's an example:

class Skeleton:

    def __init__(self):
        self.joint_groups = []

    def add_joint_group(self, group, symmetric=False):
        # quick workaround to capitalize a word, leaving the following letters unchanged
        capitalize = lambda s: s[:1].upper() + s[1:]

        processed, processed_symmetric = [], []
        for elem in group:
            if symmetric:
                processed_symmetric.append('{0}R'.format(elem))
                elem = '{0}L'.format(elem)
            processed.append(('{0}_Locator'.format(capitalize(elem)), '{0}_Joint'.format(elem)))
        self.joint_groups.append(processed)
        if processed_symmetric:
            self.add_joint_group(processed_symmetric)

    def helper_skelet(self, loc, joint):
        # your helper logic goes here
        print loc, joint

    def build(self):
        for group in self.joint_groups:
            for loc, joint in group:
                self.helper_skelet(loc, joint)
            cmds.select(cl=True)

skeleton = Skeleton()
skeleton.add_joint_group(['root', 'pelvis', 'spine', 'spine01', 'spine02', 'neck', 'head'])
skeleton.add_joint_group(['arm', 'elbow', 'hand'], True)
skeleton.add_joint_group(['hip', 'knee', 'ankle', 'foot'], True)

from pprint import pformat
print pformat(skeleton.joint_groups)

skeleton.build()

Here the code is a bit longer but it is all contained in a single object, where you could store additional data, which you get only at construction time and which you might need later on.

EDIT (to answer @Giakaama's question in the comment):

If you save the class in a separate file skeleton_class.py, you can import the class in your main.py (or whatever you want to call it), as such:

from skeleton_class import Skeleton

where the lower-case skeleton_class refers to your module (read: file) and Skeleton is the class itself. Once you've done that, you can do the same as above:

skeleton = Skeleton()
skeleton.add_joint_group(['root', 'pelvis', 'spine', 'spine01', 'spine02', 'neck', 'head'])
skeleton.add_joint_group(['arm', 'elbow', 'hand'], True)
skeleton.build()