dammit i'm trying to learn about quaternions now and I really don't like it

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The daisy chain of rabbit holes here is I thought it'd be nice to visualize some of the nested polyhedra stuff I've been working out in 2D and in construction paper models in an actual 3D geometry environment. Using FreeCAD to spawn e.g. a cube and a dodecahedron of appropriate relative size has been very straightforward. Rotating the dodeca to appropriately line up with the cube is my sudden venture into and despair at quaternion rotation.

Like, I can certainly handwavingly explain the sequence of rotations on a couple axes required to rotate the default dodeca into position. But how to communicate that as an angle and three Y, X, Z axis magnitudes is a decidedly brick-wall moment. I need to find an explainer that helps me get an intuitive grasp on this.

@aparrish @joshmillard i had to do some lightweight geospatial reasoning in code for a project a while back[0] and at one point as i stared angrily at a big sheet of paper with a lot of scribbling on it i'm pretty sure my smug partner with her smug math degree said something about quaternions and my brain shorted out.


@joshmillard game developers 🤝 geometric artists, fuck quaternions


For some peeps tryna visualize the transformations is headache inducing. As opposed to thinking of it in terms of variables and operations.

@joshmillard 3b1b has a video on visualizing which you might have seen, but in case you haven't:

Alas, it did little for me. It did increment my intuition on the subject by one unit, but not enough to motivate me to keep banging my head against the wall.

@rook Yeah, just watched that, not really breaking through the wall for me. Reasonably speaking of done very very little stuff with rotation in 3D space to begin with so I don't even really have another model to try and relate from.

@joshmillard I kinda feel the same way, although I've used rotation matrices before, but only in a workaday programming kinda way. I might be able to learn to use them in that capacity, but I don't see the value in that when I can just crib off some notes or a 3D engine or whatever to get the job done.

I have a fear that the deeper understanding I'd like to have just isn't to be found in the subject... like maybe it's somehow shallower than I think? I doubt that, but I still worry.

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