The author claims that the model importing incorrectly in Blender is Sketchfab's fault:

> Why? Because of …Sketchfab.

But he also admits that Blender's USD importer has issues:

> Sure, you can say that Blender’s USD importer is dumb, and that Sketchfab doesn’t actually remove anything, it just reshuffles and repackages stuff.

and that Apple's viewer imports it fine:

> P.S. Why does Apple’s built-in Viewer handle it just fine? I guess it’s because it understands the format on a much deeper level. Since USDZ is a technology originally developed by Pixar and Apple, the macOS viewer’s parser can correctly read even the most twisted USD file.

Given these facts, it's not at all clear to me that Sketchfab's processing step has anything to do with the incorrect import. Would the original version of the same model, as it was uploaded to Sketchfab before processing, import correctly into Blender? I don't know, but it seems very plausible that the answer is no.

This mostly seems to be an ad for the author's company.

The example usda data has a prim named `…_fbx` which suggests that maybe the original author uploaded an FBX file, and skechfab converted it to USD.

If sketchfab is converting the file format, it’s not so surprising that they get into the internals of the file.

> Yes, letting creators upload models in any structure and allowing others to download them in the exact same form can be painful.

Why though? Is this not essentially a file hosting service. How is that hard.

this is a marketing article for the author's company

This is silly.

Sketchfab clearly notes the original file format when you download a model, and lets you choose between it and various other converted formats. [Example: https://imgur.com/a/himJBfG ]

Blender doesn't fully support the USDZ format, causing the issues the author sees. [Source: https://docs.blender.org/manual/en/latest/files/import_expor... ] If the creator uploaded a USDZ file, downloaders would likely to run into similar issues.