Slash - Add-on for Blender 2.8+ onion skinning animation workflow

Hi, all

Here is my new add-on to do onion skinning for your Blender animation workflow.

Onion skinning is a technique used by animators to see multiple frames at once. By using this technique, artists can easily see how to alter or adjust an image based on the previous image in the sequence. This technique is very useful for 3d animators to see previous animation frames or the later frames at once as well.

Slash is an add-on which aims to make using onion skinning technique easier for Blender users. It provides clean and easy-to-use user interface, and will make your animation skill to next level.

You can download the sample blend file in the video here:
slash_sample_demo.blend (1.7 MB)

This add-on is available on Gumroad and Blender Market


  • Let you see earlier frames, later frames at the same time

  • Onion skinning for all frames

  • Onion skinning for a range of frames

  • Onion skinning on some specific frames which you add

  • Onion skinning on multiply meshes at the same time

  • Intuitive user interfaces, you don’t even learn to use this add-on, it tells what you can do with it.

How to install

Open Blender, go to File > User Preferences > Add-ons (or Edit > Preferences > Add-ons in 2.80), then press the “Install Add-on from File” button. Select the ZIP file that you downloaded after purchase and install it.

After installed, tick the add-on checkbox to enable it, and save your user preferences so it stays enabled.

How to use

  • After install and active the add-on, you can see the Slash panel in the Slash tab of the Property Panel.

  • Click the Active Slash Onion Skinning checkbox in the Slash panel. it will show you more UI.

  • Select a mesh or some meshes you wish to do onion animation and click Add to add it to the onion set.

  • Choose which types of frames you want to onion skinning: All Frames, Frames Range, Specific Frames.

  • Click Start Onion to see onion skinning frames

  • Adjust some settings and click Refresh Onion Objects to see the result.

  • The Slash settings you made will be saved while you save your .blend file

  • For more details, see the top video in this page.

Be sure to put your View display mode in solid mode to see opacity onion frames


Simple Descriptions of UI

Bug reports

If you encounter bugs while using Slash on Blender 2.80, please report bugs in this thread, and I will fix them soon.

Blender version

Slash supports for Blender 2.80

Get Supports:



Version 1.0.4:

  • Add on preference option to rename add-on tab name in N panel

Version 1.0.3 :

  • Fix: some edge case errors while keep original oinon without custom colors option turns on

Version 1.0.2:

  • Fix: new_object_from() error
  • Correctly handle empty type mesh

Version 1.0.1:

  • Use a better icon for added collections of objects

Version 1.0.0:

  • Can add linked collection into Slash

Version 0.1.1:

  • Frame Range - Relative: Fix showing wrong onion objects

Version 0.1.0:

  • Fix: Wrong onion objects position while turn on automatically move onion objects behind

Version 0.0.9:

  • Correctly handle alpha for onion objects while rendering

Version 0.0.8:

  • Fix: Crash while frame increment is zero

Version 0.0.7:

  • Fix: Crash while rendering animation after start onion

Version 0.0.6

  • Show onion objects while animation playback in realtime
  • Fix: Add-on crashes while active and deactive
  • Some bug fixes
  • Add an option to only preview onion objects for keyframes

Version 0.0.5

Version 0.0.4

  • Move Slash settings into Slash category instead of Misc

Version 0.0.3

Version 0.0.2

  • Add a checkbox option to move onion objects behind current object or not.
    Turning this on will prevent onion objects to overlap current object, turning this off can get a more precise location of onion objects. You can toggle this option which depends on your own need.


Version 0.0.1

  • Initial release

About features request

Features request on Slash are all welcome, please post them in this thread.



This look like a ghost tool in blender 2.79
Anyway good job I will buy it as soon as possible

Hi, drgci,

Thank you very much for your interesting.
Any suggestion is welcome, just let me know here. :smiley:

Just made a new version update, please see the Changelog above for more info

Just updated to v0.0.3 to fix a bug for the latest Blender 2.8 build due to the dependency graph API changes.

See Changelog for more info.

If you got the error, please update Slash to version 0.0.3.

Hey, just a minor update to v0.0.4.

Updated to v0.0.5
Version 0.0.5

nice! will get it once I get some funds…
one suggestion thought…since you can select specific frames to preview. Can you add an option to preview only the actual keyed frames, rather than every frame with some stepping?

Thank you.

If I understand your suggestion right, yep, you can still only preview every keyed frames while you select Specific Frames option, there is no stepping in this type of option.

I hope I understand your suggestion right. :smiley:

what I mean is to have an automatic “Specific Frames” option, that will preview your keyframes rather than every other frame.

1 Like

I see now, there will be an option added to Specific Frames which just previews all keyframes.

1 Like

Update to v0.0.6:

Version 0.0.6

  • Show onion objects while animation playback in realtime
  • Fix: Add-on crashes while active and deactive
  • Some bug fixes
  • Add an option to only preview onion objects for keyframes

Your suggestion is added to the new update. See Changelog for more details.

1 Like

I have a very simple animation of two boxes parented to two rotating bones. I selected the boxes and clicked “Add”, and I do get the ghosts. Unfortunately they appear at some distance away from the boxes, not the same distance. One is shifted like -0.5 in X and -0.5 in Y. The other is shifted like 0.5 in X and -1.5 in Y. No Z shift, and the orientation is correct. I’m not sure if it is a bug, or am I doing something wrong (very fresh newbie in blender). Thanks!

1 Like

Try to uncheck “Auomatically move onion objects behind” showed in below screenshot. And update your ghosts.

Thanks for your answer. This indeed solved this problem, meaning the onion objects are now seen correctly in when running the animation in Blender. However, when I try “Render Animation” Blender Crashes, immediately or after rendering the first frame or two. I tried this several times. When I “Stop Onion” the animation renders OK, but when I “Start Render” Blender Crashes". Also, if I -Rem the added objects, the animation renders even after “start render”, so it appears the onion objects are the problem.

My version of Blender is v2.80.75.

Thank you for your feedback.

For the crash while rendering animation with Slash, this is an known bug in Blender itself, not relative to this addon, and this issue is still not been fixed, you can checkout the issue here.

And as mentioned in the issue, there is a workaround, just make sure you check the Lock Interface in the Render menu before you start render animation. See image below.


Thanks Aaron, checking “lock interface” indeed completed the render without a crash.

However, I still get the crash from time to time when I render. This almost always happens after I change onion opacity, frame increment or frame color. I’m pretty certain the crashes are related to Slash, since they never happen when I “Stop Onion”, and I never had them before.

1 Like

As you can see in the title of that issue - Render crash when using Python API to modify object data in frame_change_pre handler. If you start onion, Slash will add that kind of handler in current scene which is for handling frame change event, and this is required in Slash, and the crash is relative to this.

We are hoping the Blender development team to fix this issue as soon as possible, although some people confirm that the workaround is working, but some are saying this workaround is not working all the time, so I will keep tracking this issue, and planning to make a perfect workaround before the Blender team fix this issue.

I will make a perfect workaround in a few days in the next update, then I will need your help to test the next update.