3D rotation: quaternion?

When working with 3D transforms, is there a way to use quaternion rotation instead of the Euler XYZ axes and the various combinations of rotation order? I'm guessing no, since I'd imagine that if it were possible it would be next to the other options in the inspector, but I figured I'd ask.

Not to my knowledge. I have some notes about a possible modifier fuse, but I didn't get much further than starting the research before I got pulled away to other projects. I'd really like to see it happen, though. Would probably be better coming from the BMD side than the community development, though, since linking a modifier to four inputs simultaneously is a bit clumsy.

There's a bunch of information about the math to convert between the two transform systems if you look up how to do it in Houdini. On my phone now but, from memory, I'm pretty sure you could do it using a Custom node in Fusion. It's one of the major subjects of Houdini when you start to use code to do things.

Thanks for the breadcrumb! Do you happen to have a link to an article or tutorial on that topic handy?