We’ve gone and supercharged Justin S Barrett’s timeless open source tool Tween Machine for all the animators out there! Our upgraded tool adds super-fast performance to the original.

Even with 1600 curves on our most complex rig Natalie, the tool remains highly interactive.

Thanks to Wade Schnieder , who’s taken up the mantle of maintaining the free version of this tool on Github .


Tween Machine working on 1600 animation curves.


Our new popup window for hotkeys greatly enhances the speed of the Tweener workflows.

From version 2.8.1a the tool now prioritises the selected curve, followed by the channel-box attribute selection. If no attribute selection is made, it will apply to all keyframes.


Alt+G Popup Window. You can also assign to custom hotkeys.


If you are using the Zoo Tools Default key set be sure to upgrade your hotkeys and use alt+g to access this feature.

See below for full hotkey installation instructions.




The Tweener smoothly transitions between the keyframes that come before and after it.

To use the Tween Machine:

– 1. Select an object/s with keyframes before and after the current time.
– 2. When you move the slider, the chosen objects will move towards the previous or next keyframe.

When released, new keyframes will be generated for all attributes that have been keyed.




Install the Zoo Tools Default hotkeys to access the Tween Machine Popup on alt+g.

You may also map to the hotkey to any custom code either in Maya’s hotkey Editor or within the Zoo Tools Hotkey Editor.

To install the Zoo Tools Default key set, open the Zoo hotkey Editor or install via the Zoo Preferences Window.


Install or Update Zoo Hotkeys. You can use your own set, this will register our commands.


After installing the Zoo Hotkeys you can switch to our default hotkey set Zoo tools Default and the popup hotkey will be “alt g”.

Or you can create your own hotkey in Maya’s Hotkey Editor.

To install a custom hotkey in Maya’s Hotkey Editor, first install the Zoo Hotkeys, this will register our commands within Maya.

Then open Maya’s Hotkey Editor and you can add your Tweener Popup hotkey to your set here:


Install the tweener Popup to a custom hotkey in Maya’s Hotkey Editor.




If you do not wish to register our hotkey commands, we have three versions of the Tween Machine popup window that can be mapped to hotkeys. All code is python.

– 1. Fast popup at mouse pointer, close on slider release.

from zoo.libs.maya.cmds.hotkeys import definedhotkeys
definedhotkeys.open_tweenMachinePopup(cursorOnSlider=True, clickOffClose=True, closeOnRelease=True)

– 2. Minimal fast popup regular window at mouse pointer for hotkeys.

from zoo.libs.maya.cmds.hotkeys import definedhotkeys
definedhotkeys.open_tweenMachinePopup(cursorOnSlider=False, clickOffClose=False, closeOnRelease=False)

– 3. Regular toolset tool with shelf at top, mixable with other tools.

from zoo.libs.maya.cmds.hotkeys import definedhotkeys

See this page for direct access to all of our hotkeys via code: Developer hotkey documentation.


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