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Python API for Maya Bifrost

Introduction

PyFrost is an object oriented Python API for Maya Bifrost. It simply wraps the cmds.vnn commands.

It it still very early and has a lot of hardcoded stuff, but hopefully it will grow nicely over time (unless Autodesk provides a proper API!)

License

The current repository is under MIT License.

Feel free to use, change, and share it as you please. You don’t have to, but mentioning my name whenever you use source code from here would be much appreciated!

API Documentation

You can find a generated sphinx documentation at https://pyfrost-maya.readthedocs.io/en/latest/

Please feel free to either submit a ticket on this repo, or email me directly at benoit.gielly@gmail.com if you find any issues. Having context would be a plus, with maybe a code snippet that doesn’t work or whatever material you used to generate the error.

Installation

PyFrost requires Autodesk Maya >= 2018 and the latest version of Bifrost, currently 2.2.0.1

You can find a module file available in pyfrost\src\module\modules\ which you can add to the MAYA_MODULE_PATH environment variable. It’ll allow Maya to pick up the whole repository automatically for you on startup.

You can always run sys.path.append() on the python source folder pyfrost\src.

Usage

Once the module is installed, all you need to do is to run import pyfrost inside Maya.

Please note that importing pyfrost.main may cause a small freeze as it’s also loading the bifrostGraph plugin, which can take some time.

Example multiply node:

import pyfrost.main

# create a new graph node
graph = pyfrost.main.Graph("multiplyNode")

# get the input node and add a "value1" float output
root = graph["/input"]
root["value1"].add("output", "float")

# you can also just stack the full path with its attribute
graph["/input.value2"].add("output", "float")

# or you can keep the ports separated if you prefer to
graph["/input"]["value3"].add("output", "float")

# create a new multiply node
# Note: you can find the nodetype in the scriptEditor by creating a node manually first.
# Then remove the "BifrostGraph," that shows up before the node type
mult = graph.create_node("Core::Math,multiply")

# to connect you can use the bitwise operator
root["value1"] >> mult["value1"]

# if a port doesn't exist on either the target or the source,
# it will try to create a new one with the type set to "auto"
root["value2"] >> mult["new_value"]

# you can also use the default method for connection
graph["/input"]["value3"].connect(mult["another_value"])

# now lets connect that to the output of the graph
mult["output"] >> graph["/output"]["result"]

pyfrost

pyfrost.api

pyfrost.api.maya

Maya Node API.

author

Benoit Gielly <benoit.gielly@gmail.com>

The intention here is to build a node API specific to each DDC (here, Maya), so in the main.py we can call that and remove the cmds calls.

When a DCC is started, the relevant API is injected in the Main one.

Note

This is a Work in Progress for now and not in use.

Example

If we were to rewrite the pyfrost.main.Graph.validate_board method, we could like that:

def __init__(self):
    self.api = Api()

def validate_board(self, name=None):
    node = self.api[name]
    if node.exists and node.type == "bifrostBoard":
        return name
    name = name if name else "bifrostGraph"
    board = api.create("bifrostBoard", name)
    return board.name

That way, all the main code remains clean of DCC commands. Obviously, each DCCs APIs must be implemented the same way for this to work.

class MayaAPI

Bases: object

Create a Maya API object.

__repr__()

Return repr(self).

__getitem__(key)

create(nodetype, name=None)

Create new node.

get(name)

Get existing node.

class MayaNode(api, node)

Bases: object

Get MayaNode object.

__init__(api, node)

Initialize self. See help(type(self)) for accurate signature.

__repr__(*args, **kwargs)

Return repr(self).

__str__()

Return str(self).

__getitem__(key)

type()

Get node type.

rename(name)

Rename node.

class MayaAttr(node, name)

Bases: object

Create a Maya Attribute class.

__init__(node, name)

Initialize self. See help(type(self)) for accurate signature.

__repr__()

Return repr(self).

__str__()

Return str(self).

property plug

Get plug.

exists()

Check if node exists.

property value

Get & set attribute’s value.

property type

Get & set attribute’s type.

add(type_, **kwargs)

Add attribute on node.

get()

Set node’s attribute value.

set(value)

Set node’s attribute value.

connect(target)

Connect current node to target.

disconnect(target)

Disconnect current node from target.

pyfrost.compounds

pyfrost.compounds.paint_delta

Create a paintDelta bifrost compound.

author

Benoit Gielly <benoit.gielly@gmail.com>

Based on the compound created by Iker J. de los Mozos: https://forums.autodesk.com/t5/bifrost-forum/paintdeltamap-compound/td-p/8972674

class PainDeltaGraph(*args, **kwargs)

Bases: pyfrost.main.Graph

Custom Graph to paint deltas between 2 meshes.

board_name = 'paintDelta'

__init__(*args, **kwargs)

Initialize self. See help(type(self)) for accurate signature.

create_graph(as_compound=False)

Create paintDelta node graph.

pyfrost.main

Convenient class used to create bifrost node graphs in python.

author

Benoit Gielly <benoit.gielly@gmail.com>

Bifrost VNN command documentation https://help.autodesk.com/view/BIFROST/ENU/?guid=__CommandsPython_index_html

class Graph(board=None)

Bases: object

Create a new bifrost graph object.

board_name = 'default'

__init__(board=None)

Initialize self. See help(type(self)) for accurate signature.

__repr__()

Return repr(self).

__str__()

Return str(self).

__getitem__(key)

get(name)

Get given string as node or attr.

property name

Get the name of the board.

property nodes

Get nodes at the board/root level.

create_node(type_, parent='/', name=None)

Create a new bifrost node in the graph.

from_json(path)

Create a compound from JSON file.

class Node(graph, parent, nodetype=None, name=None)

Bases: object

Create Node object.

__init__(graph, parent, nodetype=None, name=None)

Initialize self. See help(type(self)) for accurate signature.

__repr__(*args, **kwargs)

Return repr(self).

__str__()

Return str(self).

__getitem__(key)

attr(value)

Return the attribute class.

node(value)

Get a child of this node.

get_children()

Get children nodes.

create_node(type_, name=None)

Create a new node in the current compound.

rename(name)

Rename node.

Note

the renameNode option doesn’t return the new name, so the only way to figure out the unique name is to query all nodes, rename, query again and diff…(cool stuff, right?!)

property path

Get node’s path.

property name

Get node’s name.

property parent

Get node’s parent.

property type

Get node’s type.

property uuid

Get node’s UUID.

set_metadata(metadata)

Set node metadata.

class Attribute(node_object, attribute=None)

Bases: object

Create Attribute object.

__init__(node_object, attribute=None)

Initialize self. See help(type(self)) for accurate signature.

__str__()

Return str(self).

__repr__()

Return repr(self).

__rshift__(plug)

__floordiv__(plug)

property exists

Check if attribute exists.

property type

Get attribute type.

property value

Get and set attribute value.

add(direction, datatype='auto', value=None)

Add input plug on given node.

connect(target)

Connect plugs.

disconnect(target)

Disconnect plugs.

Release Notes

1.1.1 (2020-12-16)

• Hotfix to the from_json method that still used the previous API version

1.1.0 (2020-12-16)

• Changed attribute access across all API

Removed some logic in the API that was too complicated. It was using the __getattr__ method first to get nodes and attributes, but it ended requiring extra methods for when you wanted to pass nodes as strings like graph.node(“node”) or node.attr(“attribute”). I have removed all that and decided to use __getitem__ instead, which also prevents attribute clashing with builtin methods.

1.0.0 (2020-12-10)

• First public release

Module Index

Index