Exporting absolute shape keys

Support Animation and Rigging
1

Hi all,

I am working on a morph animation with absolute shape keys and want to export it to sketchfab, but Sketchfab seems to have a problem with Blender 4.0. And I can’t open the file in a previous version of Blender anymore. So I wanted to export a fbx. But that doesn’t seem to see the shape keys. I actually added only a key to the start of the shape key stack and a key to the end. I tried to bake the animation, but that also doesn’t seem to work: I can’t get every single shape change into a keyframe.

Help! I can’t imagine something so simple can’t work?

2

Yeah, blender 4.0 is a ‘breaking’ release, meaning compatibility problems with files from older versions of blender. One of the changes is the format of the mesh data. See here - https://blenderartists.org/t/bl-4-0-major-breakdown/1484987/4

According to those posts, blender 3.6.5 should be able to open blender 4.0 files. What version did you try opening the file with?

Never used sketchfab, but I assume with the change of how mesh data is handled in 4.0 that maybe sketchfab hasn’t updated their end to work with 4.0 files yet.

Randy

1 Like
3

It looks like Sketchfab exporter for Blender is only warranted with Blender 3.3.

FBX exporter only handle keyframes for bones or object transform animations.
If you want to animate shape keys, you have to drive them by animating bones.

You would not have this condition, by exporting a glTF.

1 Like
4

So with a gITF I can export the shapekeys?

5

With both exports, you can.
That is just simpler with glTF.
That is explained in the manual.

https://docs.blender.org/manual/en/latest/addons/import_export/scene_gltf2.html

1 Like
6

Great! Thanks! I do these kind of actions not often enough, most of the time there are several blender updates in between, so I both keep forgetting and things have changed in the mean time.

7

I now can export an animation, but it’s really ugly as if size is changed to location. The attached mp4 is how it should look (stil far from done, but I want to be sure the export works. And the sketchfab file is how the gITF looks (I imported it again in blender and there it does the same thing: Mp4 file

How the gLTB looks in sketchab or blender

I’m convinced this is probably one setting that I keep forgetting, but what am I doing wrong?

8

That looks like animated branches are starting their animation, with a negative scale.

glTF exporter options for shape keys animations are only relative to time offset.
Rest Pose options impacting scaling and location, are only for armature animations.

So, are shape keys the only setting animated or are there other types of animation in the file ?
If it is the case, that is probably an issue related to those other animations.

By default, shape keys animation for meshes, that have a constant scale at 1, should not be problematic.
Did you forget to apply transforms before export ?
Did you intentionally animated transforms ?
Did you hide such negative scaling, by animating visibility of objects in blend file ?