[Update] Bug with animation playback - Playing animations on SCALED MODELS

Update: I’ve isolated what the issue is!

The new importer is awesome! Great job :smiley: Seems it does everything properly.

There is a bug in roblox when you take a rigged model, scale it down, and play an animation on it.

Repro steps:

  1. Import one of these files (he’s a big boy!)

  2. Load an animation onto it

  3. Play the animation, it all works fine!


Now for the bug:
4) Grab the dino and scale him down to a reasonable size

The animations for certain bones end up broken in all sorts of exciting ways. Some animations seem okay, some animations don’t survive.

Expected Behavior

I’d like to be able to import my little dino friends!

Actual Behavior

Brachiosaurus.fbx (3.1 MB)
Stegosaurus_Red.fbx (3.2 MB)
T-Rex.fbx (4.2 MB)
Triceratops.fbx (1.9 MB)

Issue Area: Studio
Issue Type: Other
Impact: High
Frequency: Constantly


I would suggest re-rigging the models, and then import them as an FBX but for animation purposes only.

These models and animations correctly import to unity, if thats worth noting?


They imported perfectly for me!

Screenshot 2023-01-09 110221

Did you use avatar importer, and custom? If not, go to Plugins + Avatar Importer + Custom and then select it’s file. Then it should import correctly and you can animate them perfectly.

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They import, but the animations in them do not import correctly.

Oh I understand now. You pre-rigged them and the animations didn’t load in with them?

Update: after more testing it seems the FBX importer is indeed fine, the issue is with either scaling the model isn’t working correctly, or playing the animation on a scaled model isn’t working correctly.

How are you scaling the model?

You should try the animation resizer plugin. ROBLOX animation, when scaled, was always incorrect for me, but that plugin should fix everything perfectly.

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Pretty sure this is because the animations dont get scaled. So animations with movement will be wrong for differently scaled models, but rotations will still be fine.

With the topmost drag handle and holding shift to uniformly scale it down.

Yeah, some other people have suggested that too. Regardless, it should work! :smiley:


Hey I know this issue is super old, but just to close the loop, we shipped animation scaling recently, see this post: 3D Import Recap [Aug-Oct 2023]: Avatar Workflow Improvements and More!

Hopefully this issue is gone now, let me know if that is not the case!


yep all fixed

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