Sketchfab Forum

Stepped keyframes (as FBX)


(Hawkenking) #1

Hi, this doesn’t work.

Can we get an update on stepped animation keyframes? Seems only linear works.

Are stepped keyframes supported?
Are stepped keyframes supported?


He’s on holiday right now, but @waleguene will be the best person to discuss this. Do you have an example uploaded?

(Waleguene) #3

Hi @hawkenking,

Stepped keyframes (‘Constant’ in FBX language) are supported and Sketchfab plays it with stepped animation.

Could you check that keyframes are actually using constant/step keyframes inside the FBX (by reimporting it into the software and looking at the curves) ? or share a model that is not correctly animated so that we can debug ?


(Hawkenking) #4

Hi @waleguene thanks for the reply!

Heres the FBX
stepped (19.7 KB)

Heres the model test in sketchfab, you can see the scaling when the steps happen

Ideally they should just vanish like in this gif (stepping interpolation in Cinema4D:

(Waleguene) #5

Thanks @hawkenking!

I’m just looking into the FBX file itself and I only see “Linear”, and no mention of Constant/step interpolation in animation data. Is it correctly animated when you reimport the FBX into Cinema4D ?

(Hawkenking) #6

I’m trying upload a kind of stop motion animation that steps the scale of models to hide them per keyframe, using stepped keyframes types.

When importing to Sketchfab they appear as linear scaling.

Does Sketchfab support stepped keyframes?

(Dark Minaz) #7

there is a way to do stopmotion, but i think stepped keyframes do not work, might work in a baked version but i wouldn’t count on it.

(Simon Kratz) #8

Hi hawkenking,

as far as I know, by default, keyframe transition on Sketchfab is linearly interpolated.
You should however be able to get the results you want by matching your animation with the Sketchfab player’s fps (which is I think 60 fps?) and bake the result on export.
Then there should be no visible scaling.


(Waleguene) #9


Sketchfab uses linear interpolation by default but is able to render step/constant interpolation when keyframes are defined as such in the file.
See my answer here: Stepped keyframes (as FBX)


I’ve merged the two threads together.