- published: 18 Jan 2016
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In mathematics, the quaternions are a number system that extends the complex numbers. They were first described by Irish mathematician William Rowan Hamilton in 1843 and applied to mechanics in three-dimensional space. A feature of quaternions is that multiplication of two quaternions is noncommutative. Hamilton defined a quaternion as the quotient of two directed lines in a three-dimensional space or equivalently as the quotient of two vectors.
Quaternions find uses in both theoretical and applied mathematics, in particular for calculations involving three-dimensional rotations such as in three-dimensional computer graphics, computer vision and crystallographic texture analysis. In practical applications, they can be used alongside other methods, such as Euler angles and rotation matrices, or as an alternative to them, depending on the application.
In modern mathematical language, quaternions form a four-dimensional associative normed division algebra over the real numbers, and therefore also a domain. In fact, the quaternions were the first noncommutative division algebra to be discovered. The algebra of quaternions is often denoted by H (for Hamilton), or in blackboard bold by (Unicode U+210D, ℍ). It can also be given by the Clifford algebra classifications Cℓ0,2(R) ≅ Cℓ03,0(R). The algebra H holds a special place in analysis since, according to the Frobenius theorem, it is one of only two finite-dimensional division rings containing the real numbers as a proper subring, the other being the complex numbers. These rings are also Euclidean Hurwitz algebras, of which quaternions are the largest associative algebra.
Dr James Grime discusses a type of number beyond the complex numbers, and why they are useful. Extra footage: https://youtu.be/ISbJ9S0fzwY NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile Videos by Brady Haran Support us on Patreon: http://www.patreon.com/numberphile Special thanks to these supporters: Jeff Straathof Christian Cooper Peggy Youell Ken Baron Today I Found Out Roman Urbanovski Mehdi Razavi John Buchan Bill Shillito Andrzej 'Yester' Fiedukowicz Susan Silver Lê OK Merli Spiked Math RexDex Thomas Buckingham Peter Kær Henry Reich George Greene Arnas Pa...
This is a video I have been wanting to make for some time, in which I discuss what the quaternions are, as mathematical objects, and how we do calculations with them. In particular, we will see how the fundamental equation of the quaternions i^2=j^2=k^2=ijk=-1 easily generates the rule for quaternion multiplication. For the sake of brevity, I don't cover the famous application to 3D rotations in this video (perhaps in a subsequent one) but, of course, one must first know how to multiply two quaternions before talking about specific applications.
An overview of what quaternians are, how to do a basic rotation in 3d space, and how to use software to do it easier. Made because I thought I worked harder than I should've needed to to rotate things in 3D space myself! If you're trying to do quaternion arithmetic yourself, my favorite guide is here: http://www.youtube.com/watch?v=r9jWCbpLvHw It involves lattice multiplication, so you'd better be prepared! Khanacademy has a great primer here: https://www.khanacademy.org/math/arithmetic/multiplication-division/lattice_multiplication/v/lattice-multiplication And for a more detailed introduction, this much more personable teacher has appeared on the youtube scene since I made this video, and I've heard great things about it: http://www.youtube.com/watch?v=uRKZnFAR7yw Good luck!
We build on the idea of axis-angle rotations to start constructing quaternions. Find the source code here: https://github.com/BSVino/MathForGameDevelopers/tree/quaternions Question? Leave a comment below, or ask me on Twitter: https://twitter.com/VinoBS
Quaternions are the mathematical tool behind rotation calculation. People new in motion tracking designs could think Euler angles are more intuitive and simple than quaternions. It is in fact the opposite. If quaternions can look complicated at the beginning, this video targets to demystify quaternions and show how easy it is to use them.
Watch this video in context on Unity's learning pages here - http://unity3d.com/learn/tutorials/modules/intermediate/scripting/quaternions Quaternions are a system of rotation that allowed for smooth incremental rotations in objects. In this video, you were learn about the quaternion system used in Unity and you will explore a few of the methods that allow you to work with it. Help us caption & translate this video! http://amara.org/v/V69K/
http://demonstrations.wolfram.com/FromQuaternionTo3DRotation The Wolfram Demonstrations Project contains thousands of free interactive visualizations, with new entries added daily. Any nonzero quaternion ? has a corresponding unitary (length one) quaternion in the same direction as ?. Unitary quaternions are an elegant and efficient way to formalize 3D rotations. Contributed by: Isabelle Cattiaux-Huillard and Gudrun Albrecht Audio created with WolframTones: http://tones.wolfram.com
W. R. Hamilton in 1846 famously carved the basic multiplicative laws of the four dimensional algebra of quaternions onto a bridge in Dublin during a walk with his wife. This represented a great breakthrough on an important problem he had been wrestling with: how to algebraically represent rotations of 3 dimensional space using some kind of analog of complex numbers for rotations of the plane. This is the first of three lectures on this development, and here we set the stage by introducing complex numbers and explaining some of their natural links with rotations of the plane. There is a lot of information in this lecture, so by all means take it slowly, and break it up by pausing and absorbing the ideas before going further. In particular the last slide (page 9) could easily be stared at ...
Quaternions are like vector3's, but instead of a position in 3D space, it saves a rotation in 3D space. Unity Engine used in accordance to the Unity3D End User License Agreement, found here: http://unity3d.com/unity/unity-end-user-license-3.x.html