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https://github.com/bohdon/maya-pymetanode

A simple solution for storing python objects as data on nodes in Maya.
https://github.com/bohdon/maya-pymetanode

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A simple solution for storing python objects as data on nodes in Maya.

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# Maya Python Metadata Utils



A simple solution for storing python objects as data on a node in Maya.



Lots of metadata solutions involve wrapping the complex nature of Maya's node attribute types and quirks to allow easy

storing and retrieving of data, and connecting nodes via message attributes. PyMetaNode aims to avoid (most of) maya's

attributes altogether for simplicity and flexibility. This places the responsibility of controlling data structures

completely on the tools, and treats the nodes purely as storage.



There are several advantages of using Maya nodes for storing data vs. alternate methods, such as not requiring any other

files other than the maya scene containing the node, and the ability to undo and redo changes in nodes, and therefore

changes in data.



## Design Goals



- Simple

  - A very concise and straightforward api.

  - No need for custom plugin nodes to store your custom data.

- Fast

  - Uses Maya api for all critical operations.



## Features



- Store basic python object types (any type supported by pythons `eval`).

- Store references to other nodes inside metadata.

- Store data for multiple meta classes on a single node.

- Find any node with metadata.

- Find nodes with metadata for a specific metaclass.



## Installation



- Download the [latest release](https://github.com/bohdon/maya-pymetanode/releases/latest)

- Unzip and copy the contents to:

  - Windows: `~/Documents/maya/modules/`

  - Mac: `~/Library/Preferences/Autodesk/maya/modules/`

  - Linux: `~/maya/modules/`



> Note that you may need to create the `modules` folder if it does not exist.



Once installed, the result should look like this:



```

.../modules/pymetanode/

.../modules/pymetanode.mod

```



## Basic Usage



```python

import pymel.core as pm

import pymetanode as meta



# create some example data

my_data = {"myList": [1, 2, 3], "myTitle": "ABC"}

# data must be associated with a metaclass

my_meta_class = "MyMetaClass"

# set meta data on the selected node

node = pm.selected()[0]

meta.set_metadata(node, my_meta_class, my_data)



# retrieve the stored data for 'MyMetaClass' only

# result: {"myList":[1,2,3], "myTitle":"ABC"}

meta.get_metadata(node, my_meta_class)



# retrieve all metadata on the node

# result: {"MyMetaClass": {"myList":[1,2,3], "myTitle":"ABC"}}

meta.get_metadata(node)



# check if a node has meta data for a meta class

# result: True

meta.has_metaclass(node, "MyMetaClass")



# check if a node has any meta data

# result: True

meta.is_meta_node(node)



# find all nodes in the scene that have metadata for a class

meta.find_meta_nodes("MyMetaClass")

```



## How does it work



The implementation is very simple: python data is serialized into a string that is stored on a Maya node, and

deserialized using `ast.literal_eval` when retrieved. Each 'metaclass' type adds an attribute on the node that is used

to perform fast searching for nodes by metaclass. Data goes through a basic encoding and decoding that allows node

references and other potential future features.



## Running Tests



- Add mayapy directory to `PATH` environment variable.

- From the root directory of this repository, run `setup.sh test`