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> Quite bluntly, this all sounds like an attempt to reinvent euclidean geometry following a convoluted way. I mean, what does all this buy you that applying a subset of affine transformations (scaling, translation, rotation) to an orthogonal coordinate system doesn't give you already?

It is attempting to reinvent Euclidean geometry, yes. I don't think it's convoluted though.

To give a prime example, take the article we're commenting on: interpolating rotations. Or more generally: interpolating transformations. Just doing this with rotations without suffering gimbal locks already brings you to quaternions. Are quaternions 'convoluted'?

The fact that all objects are native to the algebra means they're composable. Take for example this slide of the formula of a 4D torus in coordinates, and in 4D PGA: https://i.imgur.com/T4hofL2.png The talk in general has a bunch of example applications: https://youtu.be/tX4H_ctggYo?t=4232

Questions such as "the intersection of this line and this plane", "the line through two points" "the circle where these two spheres intersect", "the point at the intersection of three planes", "the projection of this line on this plane" and such are trivial, native (the resulting object is part of the algebra) and exception-free in geometric algebra. E.g. two planes always intersect, it just happens that the intersection is a line at infinity if they're parallel.

The exact same code used to translate and rotate a point around the origin can be used to translate and rotate a line, or a plane around the origin.

Also note that most of computer graphics already realizes that embedding our geometric space into a larger space is useful. Projective geometry (embedding 3D into 4D) is already everywhere, because it unifies translations and rotations into a single concept (matrix multiplication). Geometric algebra simply goes a step further.



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