Isner's page on quaternions is still up, and it's still more than OK if you haven't bumped into it: http://www.isner.com/tutorials/quatSpells/quaternion_spells_14.htm
Personally I've never quite understood the struggle with quaternions and rotations, I think most of it comes from the fact people are too used to numbers that have a Newtonian intuitiveness on a linear scale to them, and therefore are puzzled by the fact that the numbers in quaternions are not to be intuitively read and translated in your head the way Euler angles in a gimbal system or scalars in vector maths are. The basic concept of direction + roll and interpolation being "warped" in spherical space is not that un-intuitive to understand though. The rest is all down to simple matrix maths, which again tend to be overly mystified and puzzling to many, but if explained well and if segwayed from their 3D application (rather than from the abstracts of linear systems and general matrix composition) tend to be very intuitive. On Mon, Jul 22, 2013 at 8:10 AM, Leonard Koch <[email protected]>wrote: > I recently had to properly understand rotations on a low level and an > article written by you would have been awesome. > On Jul 21, 2013 9:19 PM, "Alok Gandhi" <[email protected]> wrote: > >> Thanks for your kind words Andy. I am planning a few more. This gives me >> opportunity to ask people here which concepts, areas of 3D mathematics are >> most difficult to master so that I can try to cover them up at my blog. >> >> The ones that I have in mind are : >> >> 1. Rotations - What the hell are quaternions, eulers etc. >> >> 2. Transforms and Matrix - why do we need them. >> >> 3. Half float precisions numbers and how exr uses them. >> >> 4. The math behind the stereoscopy. >> >> >> >> On Sun, Jul 21, 2013 at 2:47 PM, Andy Moorer <[email protected]>wrote: >> >>> Alok since you bring it up I am reminded to belatedly thank you for this >>> article - it's a fantastic read, and your blog is a personal favorite. >>> >>> >>> -- Our users will know fear and cower before our software! Ship it! Ship it and let them flee like the dogs they are!
