Coincidentally, I help develop the Bevy game engine, and I was just talking to people about working on a bevy_usd library. From what they told me, USD is extremely complicated, and the "spec" is basically just the C++ source code. I was warned not to bother. Imo it would be better if glTF just got more support and extensions.
A full Rust port of OpenUSD would be very ambitious. It's quite complicated (e.g. the OpenUSD composition rules) and depends on other vfx c++ libraries.
I've been experimenting with implementating a subset of OpenUSD in Rust, but there's lots of challenges given the original codebase. E.g. the c++ code uses lots of base classes, downcasting and there's no lifetime information. It's possible to port these across, but gets ugly in the details (e.g. trying to avoid non-static downcasting in Rust). It would take a lot of effort to do a total idiomatic rewrite given the size of the codebase and how interconnected the pieces are in OpenUSD. I still think it's worth pursuing though, OpenUSD is great.
Projects that want leaner dependencies, like everything on the web, don’t yet have a good way to work with USD.
Did the web suddenly switch to WebASM overnight or do we have a different definition on "lean dependencies"? using any of the popular JS frameworks seems to bring in a few hundred dependencies alone.