GLB files compressed with etc1s and/or draco can't be uploaded

To reduce file size, I’m usually optimizing models before upload to have tight control over texture and mesh compression parameters. However, it seems that the files cause an ERROR 13 (CONTACT SUPPORT) and don’t properly upload.

To reproduce, compress any model with gltf-transform etc1s in.glb out.glb and/or gltf-transform draco out.glb out2.glb and try to upload that.


Sorry, we don’t support draco compression. I have not seen etc1s, but I strongly suspect we don’t support that either.

It’s not currently planned to support this, but maybe in the future.

Regardless, we do a lot of our own compression to optimize models for the viewer which you would not have control over, and it wouldn’t really make sense in our current workflow to support draco.

However, if you’d like to provide your draco-compressed versions for others to download, you can add them as part of an Additional File archive:

Thanks for verifying. You might want to clarify the error message, instead of a generic “contact support” message. Compression formats such as Draco, Meshopt, ETC1S and UASTC are on the rise and likely more people will encounter this problem.

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