Blendshape Groups

A simple library to expose blendShape groups.

BlendShape groups have absolutely no access point with Maya's existing apis, except from a few obscure mel commands.
Though these mel commands completely rely on Shape Editor selection, making it impractical to write code with it.
This library exposes methods to easily modify and manage a blendShape's groups.

Installation

Simply put the script where your PYTHON path is pointing to, so that the module ca be imported.

Supported versions

This library was tested in Maya 2018 Extension 4.
It was also written to be compatible for both Python 2 and 3, so it should work with Maya 2017 and above.

Usage

First import the module:

import blendshape_groups

Then to test on an example, let's create a poly sphere with a blendShape and some targets:

# Create a poly sphere and add a blendShape to it.
cmds.file(new=True, force=True)
cmds.polySphere(name="sphere")
blendshape = cmds.blendShape("sphere")[0]

# Add a bunch of blendShape targets.
food = {"apple": 0, "banana": 1, "carrot": 2, "durian": 3, "eggplant": 4, "fennel": 5}
for name, index in food.items():
    cmds.blendShape(blendshape, e=True, target=["sphere", index, "sphere", 1])
    cmds.aliasAttr(name, "{bs}.w[{idx}]".format(bs=blendshape, idx=index))

What example above creates in the Shape Editor

Pass the blendShape to the class:

shape_grps = BlendShapeGroups(blendshape)

Now we can begin managing the blendShape's groups.
Here's various methods that can be used:

# Create an empty group called 'Market'.
market_index = shape_grps.create_grp(name="Market")

# Create a group called 'Fruit' with a bunch of targets, and parent it under 'Market' group.
shape_grps.create_grp(
    name="Fruit", targets=[food["apple"], food["banana"], food["durian"]], parent_grp_index=market_index)

# Create another empty group called 'Veggies'.
veggies_index = shape_grps.create_grp(name="Veggies")

# Add targets to 'Veggies' group.
shape_grps.move_targets([food["carrot"], food["eggplant"], food["fennel"]], veggies_index)

# Move 'Veggies' group under 'Market' group.
shape_grps.move_grps([veggies_index], market_index)

# Print a list of all available group indices.
# Output: [0, 1, 2, 3]
print(shape_grps.get_all_grp_indices())

# Print a list of all group indices parented under 'Market' group.
# Output: [2, 3]
print(shape_grps.get_grp_indices(market_index))

# Print the number of available groups.
# Output: 4
print(shape_grps.get_grp_count())

# Print a list of target indices from all groups.
# Output: [0, 1, 2, 3, 4, 5]
print(shape_grps.get_all_target_indices())

# Print a list of target indices from 'Veggies' group.
# Output: [2, 4, 5]
print(shape_grps.get_grp_target_indices(veggies_index))

# Iterate over all groups.
for grp_index in shape_grps:
    grp_name = shape_grps.get_grp_name(grp_index)
    print(grp_index, grp_name)
    # Output:
    # 0 Group
    # 1 Market
    # 2 Fruit
    # 3 Veggies

# Rename 'Market' group to 'Fruit Market'
shape_grps.rename_grp(1, "Fruit Market")

# Delete 'Veggies' group including all of its targets.
shape_grps.delete_grp(veggies_index)

# Delete 'banana' target by using its index.
shape_grps.delete_target(food["banana"])

Final result with new groups in the Shape Editor

Reporting a bug / Requesting a feature

If you run into any bugs or have a request to extend this library, then please create a new issue from this repository.