mango package

Django inspired metadata framework for Maya.

Installation

  • Extract the content of the .rar file anywhere on disk.
  • Drag the mango.mel file in Maya to permanently install the script.

Usage

The userSetup.py registers callbacks that will automatically process the scene when a file gets Imported/Opened or a reference gets Created/Loaded. This will allow instant easy access to the models.

Models

Create

A model can be created by inheriting from a base class. Fields and relations can be added to the class using descriptors. There is a wide variety of fields and relations to choose from. Both fields and relations have base classes that can be inherited from to generate new types.

from mango import models
from mango import fields
from mango import relations

class Joint(models.Model):
    node_type = "joint"
    number = fields.IntField(default_value=10, unique=True, keyable=True)
    link = relations.OneToManyRel(rev_name="link_reverse", typed=True)

class Collection(models.Model):
    node_type = "transform"
    joint_set = relations.OneToManyRel(Joint, rev_name="part", typed=True)

Initialize

Once the class is created you can either initialize a model by creating a new node calling the class using keyword arguments or you can initialize an existing node by provided the name of the node. In both events attributes for the fields and relations are created.

# create new nodes
l_elbow_jnt = Joint(name="l_elbow_jnt", number=1)
l_wrist_jnt = Joint(name="l_wrist_jnt", parent="l_elbow_jnt", link=l_elbow_jnt)

# initialize existing nodes
l_elbow_jnt = Joint("l_elbow_jnt")  # initialize using string
l_elbow_jnt = Joint(l_elbow_jnt.object)  # initialize using OpenMaya.MObject
l_elbow_jnt = Joint(l_elbow_jnt.dependency)  # initialize using OpenMaya.MFnDependencyNode

Fields

Fields can be retrieved and set using the descriptor. Validators are attached to each field to ensure values can actually be set on the node.

print l_elbow_jnt.number
l_elbow_jnt.number = 5
l_elbow_jnt.number = "10"  # raises TypeError

Relations

Relations can be retrieved and set using the descripter. Validators are attached to each relation to make sure that only the right typed models are added as relations and the unique state of the model instance using its unique fields.

print l_elbow_jnt.link_reverse
print l_wrist_jnt.link.all()
l_elbow_jnt.link_reverse = None
l_wrist_jnt.link.add(l_elbow_jnt)

Managers

Manager objects are attached to the model types and to the relations. Only when a relation is not singular a manager object will be returned. This manager object can be used to Create/Set/Add and Remove model instances.

l_shoulder_joint = Joint.objects.create(name="l_shoulder_jnt")
print Joint.objects.all()
print Joint.objects.filter(number=10)  # operators allowed using '__'
mango.refresh()

The refresh function removed any mango modules from the sys modules dictionary. Before doing this any existing callbacks will be removed as they will be recreated once models are initialized.

If any classes inherit from mango but do not live in the package the inheritance will be broken. Those modules will have to be reloaded as well but that is up to the user to organise.