[Rotation of objects using quaternion]

[OGLB]

Hello Guys, I hope you’re all doing well.

So I have a scene in which I added a cube and tried to rotate it using a quaternion.
I also attached a coordinate system to it where x is the red axis, y is the green axis and z is the cyan blue axis as shown in the picture below:

But I’m wondering, if I use a quaternion to change the orientation of the cube, it rotates with respect to which coordinate system exactly? does it rotate with respect to OpenGL standard coordinate system; I mean the one represented in the picture below:

or the coordinate system attached to my cube.

[I applied the rotation using a quaternion then I drew the cube and then I drew its coordinate system]
Thank you All.

[Dark_Photon]

I’m not sure what your real reason for using quaternions is, or your real concern about using them (your question is puzzling), but see this:

• The Matrix and Quaternions FAQ

It’ll likely answer your question.

Search down to Q47 and start reading about Quaternions. Also see mentions of Euler Angles, as well as Gimbal Lock.

Quaternions define a rotation axis (in some parent coordinate frame you define) and an amount of rotation about that axis.