Roll and pitch relative to device, yaw relative to earth

[copumpkin]

Apologies if I’m misunderstanding here, but as I understand it Fusion’s 3 orientation reference frames are relative to earth in all 3 coordinates.

I’m trying to derive roll and pitch relative to my IMU, and earth-relative yaw, so effectively I’d get a “compass” reading from yaw, but I can easily determine if the IMU has tilted side to side or front to back and isolate sideways tilt from front/back tilt.

To achieve this, it seems like I could use yaw straight out of Fusion but to get my device-relative pitch and roll, I’d have to adjust the other two Euler angles by my yaw using some trig. Is that correct or am I misunderstanding the convention?

Also, if the above is roughly correct, which yaw values correspond to north/south/east/west?

Thanks!

[xioTechnologies]

Fusion uses the ZYX Euler angles sequence with an axes convention selected in the settings, either NWD, ENU, or NED.

It sounds like your enquiry is not about Fusion and you just need clarification on what Euler angles actually are. I suggest you search online. There are countless YouTube videos that do a far better job of explaining Euler angles with animations than I could do in written comments.

[copumpkin]

You're right! I think I was having some issues with my inputs into Fusion which was then producing counterintuitive results which led me to think I was getting the wrong frame of reference. After some tinkering I think it's behaving more in line with how I'd expect now, thanks!