Question

i have been studying unity3d for a few months and i have done some research of this mathematical concepts that we can use when moving / rotating a object.

I have read some mathematical explanations, but i cant see how it would apply/fit my needs on unity3d.

Can anyone point me out a good material about these two concepts or try to explain me when im gonna need to use quaternions and slerp? Why do i have to use it? When?

I will appreciate any help that i can get.

Answer 1

You need them because rotation using Euler space (3 dimensions) does not result in smooth rotation, and since arbitrary rotations must be done in multiple steps (about each axis), it is actually possible to collapse one of the dimensions during a rotation and break an animation.

Quarternions and slerp (spherical linear interpolation) uses 4 dimensions (includes imaginary number space) to perform rotations smoothly and in one single step. Almost all games and computer animations use this math to perform rotations, and some of the best tutorials for its use are thus taught in computer animation courses.

So by googling “Quarternion Computer Animation”, you get some of the better articles and slide-shows. I’d start there.

Here’s a fairly good one that doesn’t seem to skip any steps. A brief overview on using matrix notation to perform transformations is important, and this has that covered: http://www.keremcaliskan.com/a-tutorial-on-computer-animation-ii-2/