Onion Skin Tools v0.2.0

by Joel's Blender Addons Store in Scripts and Addons

Onion Skin Tools will be receiving an update for Blender 2.8 after its official release. The Blender Python API is still subject to change until that time.

Object Onion Skinning For Blender

Your animation workflow is about to level up. 

What's This About "Onions?"

You may be familiar with the term onion skinning, a traditional animation technique that enables the animator to see previous drawings through the page while drawing a frame.  The effect is so essential to an efficient hand-drawn animation workflow that the majority of digital 2D and 2.5D animation packages include onion skinning features natively.

Which, you know, makes total sense. Having a visual reference for previous or later frames, the animator can make informed decisions while toiling away on the current frame.  As Jim Gaffigan says, "It's so simple."

3D animation applications are often the exception. 3D applications generally forgo robust onion skinning features and animators are expected by their applications to animate 'in the blind.'  

So What Does Onion Skin Tools Do?

Very simply, this:

Onion Skin Tools provides animators with object onion skinning in Blender’s viewport.  Visualize the action of your animation instantly without even moving the timeline cursor!  No more animating in the blind!

With Onion Skin Tools, you can

  • Generate onion skinning for any mesh-able objects, even entire multiple-object characters or creatures, on arbitrary frames or over a user-defined frame range.
  • Make informed posing decisions! Compare poses on previous and later frames side by side while you pose your character or creature rig on the current frame. 
  • Stop guessing! See at a glance the arcs of your action without even changing the current frame.

                          (Realtime screencast of Blender viewport courtesy of www.pintamonos.cl)

Whether you're animating characters, creatures, vehicles, text, motion graphics, or something else entirely - 

It’s time to take the guess work / incessant timeline scrubbing / pose memorizing out of your animation workflow.


Bugfix version 0.2.0 - 8/24/18:

  • Hotfix for issue with incorrect display of onion skinning of linked rig moved in the scene by group controller. For now, this assumes the linked rig isn't duplicated in the scene.
  • Addresses problem with onion skinning only current frame.
  • Fix for naming conflicts involving multiple character sets.
  • More robust and intuitive removal of onion skinning.
  • Compiled module is removed.

Bugfix version 0.1.6 - 9/25/17:

  • Fixes various error messages in console and some unpredictable behavior when removing onion skinning. These errors arose in the code overhaul when introducing character sets. Generating / removing onion skinning now should be more predictable and stable. 

New features 9/14/17:

  • Character Sets - The only new major feature in version 0.1.3, Character sets allow you to create sets of objects to be onion skinned, and control each set's onion skinning generation, removal, and viewport settings independently!

Changes since v0.1:

  • UI changes for Character Sets and drop down arrows for tidying up areas of the UI that aren't in use.


  • Fix for apparently erratic issue of using bpy.utils.previews, which varies between Blender builds. Custom icon loading code would fail and caused addon display to fail. Now, if icon loading failes, the UI will display but without icons.

New features 8/2/17:

  • Auto Updating - A primary feature of this release! When enabled, Auto Updating will watch for changes to an Updater object (e.g., a character rig armature) and automatically update the onion skinning according to the changes!
  • Transparency Range control - An optional range control has been added to display onion skinning only on frames within a specified range around the current frame as you move through the timeline.
  • Absolute Range mode - A new mode for setting the frame range has been added. Choose Relative (legacy, default) or Absolute. Absolute mode allows you to set specific start and end frames to generate onion skinning (e.g., frames 1 - 100).
  • X-Ray Originals - Quick access toggle for enabling X-Ray draw mode on original objects has been added, which will draw original objects over onion skinning.
  • Backend work - Onion Skin Tools now sports compiled Cython modules for slightly faster onion skinning (re)generation. Currently, compiled modules are only provided for 64-bit Windows / Linux. 32-bit and Mac systems are still supported with pure Python.


  • Compatibility fixes for Blender 2.77 where addon wouldn’t display correctly.
  • Pre-2.78 fix for broken onion skinning removal.

New features 7/21/17:

  • Support for linked libraries.
  • Optional frame number drawing over onion skinned frames.
  • UI overhaul to reduce visual clutter.

Getting Started


You can install the addon one of two ways.
1) Extract the onion_skin_tools folder from the .zip file and move or copy the folder directly to your
<blender installation>/2.78/scripts/addons directory.  
2) Alternatively, from within Blender:
   • Go to File > User Preferences > Addons.
   • At the bottom of the User Preferences window, click “Install From File...”  
   • Browse to the .zip file, select it, and click “Install From File.”
3) From the User Preferences window, navigate to the Addons tab, and select the Animation filter.
4) Click the checkbox next to “Animation: Onion Skin Tools” to enable the addon.
5) Click “Save User Settings.”

Features & Settings

This is the addon panel. After enabling the addon, you will find this panel in the 3D View > Tools Panel > Animation Tab.  Familiarize yourself with the following settings.  
A quick note: In this documentation, we’ll be verbing the phrase “onion skin” for the sake of convenience. Hope you’re okay with that.

Going Further


Once you’ve familiarized yourself with the settings, using the addon should be fairly straightforward. Briefly, the steps are:
1) Add objects to the list of objects to onion skin.
2) Adjust frame range settings.
3) Click Run.
4) After animating, click Remove to remove onion skinning from the viewport.

Adding Objects

To add objects to the list for onion skinning:

  1. Select one or more mesh objects.
  2. Click the '+'  button to add the selected objects to the list.
  3. If the selected object is an Armature, the armature will not be added to the list. Instead, any mesh objects parented or deformed by the Armature will be added to the list. This way, you can quickly add a whole rigged character to the list for onion skinning.
  4. To add objects from a linked group (say, a linked character rig), select the group Empty and click the '+' button to add the linked objects to the list.

Removing Objects

Click the '-' button to remove the selected list item.

Adjusting Settings

Enable Current Frame Only to run onion skinning on only the current frame. Enabling this will remove several items from the user interface (specifically, the Include Current Frame, Direction, range Backward / Forward settings).  

Keep Current Frame Only disabled to run onion skinning on a range of frames.

Enable Include Current Frame to include the current frame in the onion skinning.

Set the frame range direction.
Backward will only include frames earlier than the current frame. Forward will only include frames later than the current frame. Both will include frames earlier and frames later than the current frame.

Set the frame range. The Backward slider sets the number of frames earlier than the current frame to onion skin.  The Forward slider sets the number of frames later than the current frame to onion skin. The Frame Step slider sets the number of frames to progress between onion skinned frames. A value of 1 will onion skin every frame. A value of 2 will onion skin every other frame, etc.

Now you can run the onion skinning process by clicking Run.

Settings That Update In the Viewport

The following settings will update the onion skinning objects in the viewport. Therefore it is not essential to set these before running the onion skinning operator.

The Earlier Color and Later Color properties determine the color of onion skinning objects earlier and later than the current frame. The Transparency Factor slider is a multiplier for onion skinning transparency.  

Note: After running onion skinning, changing the current frame on the timeline will update the color and transparency of onion skinned frames relative to the new current frame. For example, frames earlier than the current frame will turn blue (or your custom color) and become more transparent as you move forward on the timeline.

Enabling or disabling X-Ray will enable or disable x-ray drawing on the onion skinning objects.

To hide onion skinning objects before the current frame on the timeline, enable Before. As the timeline cursor progresses forward, any onion skinned frames prior to the current frame will disappear from view.
Likewise, to hide onion skinning objects after the current frame on the timeline, enable After. The All checkbox is a convenience - you can use a single checkbox to hide all the onion skinned frames from view, but this is also accomplished by enabling both Before and After.

Removing Onion Skinning

To remove the onion skinning from the viewport, click the Remove button.  

To remove onion skinning only on the current frame (assuming of course the current frame is onion skinned), check Current Frame Only and click Remove.


You can onion skin a single frame, then progress forward a few frames on the timeline, and onion skin another frame.  Using the Current Frame Only setting, you can onion skin an arbitrary number of frames individually to maintain control over what you would like to see in the viewport while you animate.

Have Fun!

What can I expect from future development of this addon?

There is already a sizable list of ideas for improvements, enhancements, and features that will each take at least a little time to implement.  Some of these are small improvements, e.g. a checkbox added to the UI for quick toggling of a visualization feature. Some of these are large in scope, requiring significant additions to the onion skinning generation code and completely redesigning parts of the UI. So you can expect the improvements to continue for quite some time! :)

Onion Skin Tools may reach a place of stasis in the distant future, after many or all of these items have been worked into the addon, and most of the improvements being made are compatibility fixes for newer versions of Blender. But I'll listen to my users - as long as you keep asking for improvements, I'll keep looking into them!

Does Onion Skin Tools support instanced groups from linked libraries?

Yes!  Onion Skin Tools supports linked instanced groups (e.g., character rigs).  

When you want to onion skin an instanced group linked from another .blend file, you'll simply need to select the group's Empty object, and click the button to add objects to the onion skinning list.  This will add the linked meshes to the list, and then you can run the onion skinning operation.

Does Onion Skin Tools affect viewport performance?

The answer, of course, is a resounding "That depends!" :D  Generally, though, the difference is altogether unnoticeable; when there is a difference, it's negligible.

Remember that viewport performance boils down to the density of the scene being displayed and to your particular graphics and computing hardware.  If you're onion skinning a very dense character mesh over many frames, then you may experience a slowdown of viewport performance, playback, or navigation.  Blender's viewport drawing code is redrawing a duplicate of your character multiple times.  Use your best judgment!  Only include what you need to see in the onion skinning, and leave out denser extraneous meshes.

Item Rating

This item has an average rating of 5 from 10 ratings by the community.

  • yarmyen 3 days ago

    I look forward to in the blender 2.8 version
    It's important add-on of me.

  • Looch 3 months ago

    Its still a lovely addon, do you think you'll update it for 2.8?

    • Joel 3 months ago

      I absolutely intend to. I'm not sure how much the Python API will be changing for the 2.8 release, so there may or may not be a bit of work to do before I can get an updated add on out for 2.8. But it'll certainly be coming!

  • Alex 10 months ago

    Looks cool and all ,but the AutoUpdate doesn't work makes blender 2.77a 2.78 and 2.79 crash

    • Joel 10 months ago

      Hi, I'm sorry you're having trouble with it. I haven't run into this issue myself or heard about it from anyone else. I'm looking into the issue but I'll need some help tracking down the source of the trouble you're having.

  • Sergio 10 months ago

    This addon is exactly what I was looking for... I can't thank you enough! :)
    Is this addon going to work with 2.8? Are you planning on updating it once the 2.8 is out? Superb job!!

    • Joel 10 months ago

      Hi there, thanks for the kind comment! I am indeed planning to keep it up to date for future releases.

  • Pawel Gasiorowski about 1 year ago

    Quite handy plugin - massive kudos!

  • SergioCajazeiras Cajazeiras about 1 year ago

    How I needed it! very good thank you!

  • Vassilis Kakoulantonakis over 1 year ago

    Thank you Joel for this amazing addon. This is a MUST HAVE for animators! Thanks again!

    • Joel over 1 year ago

      Thank YOU for your appreciation! I'm glad you're enjoying the addon.

  • Coverop over 1 year ago

    If you like to animate... but Blender gives you this "UGH" feeling.
    Get this addon.

    • Joel over 1 year ago

      Thanks for the compliment! I can relate to the frustration of animating without a consistent point of reference.

  • richardkhoa over 1 year ago

    I am an experienced animator and a big time animation nerd. When I first saw this addon, I thought it looked cool and wanted to try it out. And now I report back that it's really fun to play with. I found myself going back to old projects I did and running the onion tool. Really enhances my love for animation :) super fun to play with!

    I highly recommend any beginner animators to get this addon. It will make learning, practicing, and working so much more fun!

    Also I rate Joel's customer service 5/5 he responded within a few hours or so and with a quick fix! Works with 2.77 now :) Thanks Joel! Hope you create more cool tools for us to use

    • Joel over 1 year ago

      Thanks for the kind words! Glad I could help with the issue, and thank you for bringing it to my attention.

  • Ellie over 1 year ago

    So, two weeks ago, I was up animating a walk cycle. It went something like this: edit pose, scrub timeline. Fantasise about object-based onion skinning. Curse total absence of programming skills. Edit pose, scrub timeline. Edit pose. Forget how previous pose looked. Scrub timeline. Edit pose. Consider making deal with Satan. Repeat ad nauseam.

    It was especially difficult for me, as a fairly inexperienced animator coming from a 2D background, working without onion skinning. It was like practicing sharpshooting with a blindfold on, as I’m sure any Blender user will attest.

    So, I just have to say: Joel, you are most certainly a creator after my own heart!!!! Not only does this addon make animating infinitely easier, quicker, and more accurate, it makes it so much more enjoyable!

    Not only is this creator very talented, but he has clearly put a tremendous amount of thought, time, and effort into making this addon. The addon itself is incredibly simple and easy to use, while packing in all the essential features you need. The best way to describe it is that it simply *makes sense*. I am sure it will fit in seamlessly into any animation workflow.

    Also, as someone with ADHD: thank you, thank you, thank you for your fantastic streamlined documentation. Like everything else about this addon, it just makes sense. It is very short, simple, concise, with clear instructions and an annotated picture of the menu item. I read through it once and was ready to go.

    Overall, I seriously cannot recommend this enough to anyone who animates in Blender. Joel is certainly a creator to keep an eye on. To you, Joel: you have most definitely earned yourself a loyal supporter! I am enthusiastic to see what other wonderful things you will create in the future.

    To everyone else: Let this addon take off your blindfolds!

    • Joel over 1 year ago

      Ellie, I'm very pleased to hear you're getting so much out of the addon! I already have the groundwork laid for some new features and enhancements, so I'll be letting you know soon when the new version is available for download. In the meantime, please do let me know if there's anything you come across that needs improving. And thank you so much for your kind words!

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