Rotations can be dizzying to think about, so this sort of issue is maybe best visited casually over a period of time rather than jammed into an intensive study session.
That said, the wikipedia page on Gimbal Lock can help motivate an understanding of why a person might want to use quaternions to represent rotation in three dimensions. Thanks, -- Raul On Thu, Nov 1, 2018 at 2:46 PM Brian Schott <[email protected]> wrote: > > With pleasure I watched the two videos you linked. The professionalism of > the presentation is unprecedented in my experience. > > I was unable to view the additional interactive video which was touted so > highly there. Apparently my computer is ill-equipped for that technology. > > On the other hand, in addition I found the following video by the same > author to be more basic and helped my a lot until the very end where the > author tried to explain the geometric connection between x->e^x . That blew > me away. But what was very helpful was seeing how complex numbers can be > seen as combining a translation in the real dimension and a rotation in the > imaginary dimension. > > https://www.youtube.com/watch?v=mvmuCPvRoWQ > > Well, to be honest, I got very lost in the longer one, and was hoping that > others would reply to your chat and give me some perspective on just how > valuable and reachable these videos are. > > But no one seems to have directly commented on these videos and the > comments in Raul's thread seem to choose other interpretations (such as > time and 3 distances, I think), I am not any clearer on the usefulness of > quarternions, especially for rotating 3d spaces, which I have enjoyed > exploring myself using J and 4x4 shaped matrices. But even that exploration > has been hampered for a few years now because I have not been able to use > opengl or other graphics systems with . > > So this has been a rather frustrating period of time relative to graphics > endeavors anyhow. > > > On Sat, Oct 27, 2018 at 3:00 AM 'robert therriault' via Chat < > [email protected]> wrote: > > > There is a channel on youtube called 3blue1brown where Grant Sanderson > > does exceptional math videos. I have heard interest in quaternions > > expressed in the J community so I will put in some links that provide > > visual explanations of quaternions and how to visualize their actions > > across 4 dimensions. > > > > Initial video introducing quaternions: > > https://www.youtube.com/watch?v=d4EgbgTm0Bg > > > > Short video introducing an interactive tool to investigate quaternion > > behaviour: https://www.youtube.com/watch?v=zjMuIxRvygQ > > > > Site containing the interactive videos https://eater.net/quaternions > > (yes these videos are interactive and can be manipulated in real time!) > > > > Enjoy > > > > Cheers, bob > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > -- > (B=) <-----my sig > Brian Schott > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
