Hi, I’m trying to figure out how to find a quaternion between two directly opposite vectors, eg. vectors with a 180 degree angle between them. For example, such vectors are [(base) end)]: [ {0,0,0) (1,0,0) ] and [(0,0,0), (-1,0,0)]. From what I’ve read there could be an infinite number of rotations between such vectors. I just need a formula to find any one of those.

I tried to find quats between a few vectors with almsot 180 degree angles between them, and all those quats(w,x,y,z) looked like q=(0, cos x, -sin y, 0) or q*-1, where x+y=pi.