Maya->GLTF - Release 20210507.3 Increases File Size by Around 30%

Hi all,
first of all, thanks a ton to everyone working on the Babylon Exporter for Maya, it’s been an immensely useful tool for my team and I.

I recently updated to the latest version of the exporter for Maya 2020 and found that when exporting to gltf, my bin files increased in size by about 30%. I tried out different versions and found that this change was introduced with release 20210507.3, which has the changelog “Add 8 bone export support for Babylon->GLTF”. I can also confirm that the difference in file size persists when using the “Optimize Vertices” and “Use Draco Compression” options.

I’m attaching an example of a very simple Maya file (a rigged cylinder) and the resulting exported gltf and bin files using exporter versions 20210507.3 and 20210506.7 to demonstrate what I’m seeing. Would anyone have any insight into what’s going on and be able to fix it? Thanks a lot. (214.5 KB)

adding @Guillaume_Pelletier

Had a look, it’s seems that one of your bone has more than 5 influences (weight), so the exporter is taking this in account and add an extra room for 4 more weights (8 instead of 4), then it’s perfecly legit to get a file increase. The fact that the file was smaller before is because the the 5th weight was never taked in account (which was a limitation). So basically the file increase is normal, and optimizing your weight might optimize the final size (keep only 4 weight if you can, because often time we got weight at 0, which take room for nothings.).

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Got it, thanks for the clarification! I did a quick test by limiting the number of influences per vertex to 4 and confirmed that the two exporter versions result in the same file size.