Help Needed Learning Quaternions (Or at least how to use them)

I'm embarking on a journey to understand how quaternions work (at least well enough to use them for rotations in Unity), but so far I've been striking out looking for easily digestible information online. I think this may be because it's just not information that can be easily simplified, and maybe asking for a beginner's guide to Quaternions is just asking too much. But I've hit a wall and I'm looking for any advice.

If anyone out there can offer help in understanding, or suggestions for learning sources, it'd be a huge help. For reference, here's the original problem I'm trying to solve:

I need to rotate one point, about another point, by x degrees.

Its basically the same as if I had a GameObject A parented to a GameObject B (which has a different position than A), and then I rotated GameObject B. In that case Unity will just do the rotations for you behind the scenes, but I'm in a situation where that won't work, and I need to know how to rotate the vector entirely with math.

I've been attempting to learn this stuff for a long while now with little luck, and any help or leads would be greatly appreciated.

Thank you,
Orion

 

You could use transform.Rotate(); which takes a vector3 or even EulerAngles

 

Unfortunately, I don't think transform.Rotate() or transform.RotateAround() can work in my case, since I need to rotate a point represented by a Vector3 in my script (not a GO), so there won't be a transform involved.

I don't mean to shrug off your help, though. Please let me know if I'm wrong, or if you know any other solutions.

Thanks!

 

you might also try using transform.RotateAround() ...
http://unity3d.com/support/documentation/ScriptReference/Transform.RotateAround.html

 

can I use either of these methods if I'm trying to rotate a virtual point (vector 3) in my script, and don't have a transform involved? I'm not meaning to rotate a GO.

 

From my experience there is no reason to learn about Quaternions unless you have an interest in them. You can do everything in Euler and just use the inbuilt functions to convert between.

For what you're doing specifically, I generally just cheat. I change the objects pivot point to the point where I want to orbit around and just do a normal rotation. I really should get around to writing a solid orbit script sometime though.

 

oops I did not see your reply to appels, or get it that your target is also only a coordinate value and not a GO.
Those functions do make the calculations a lot easier ( or rather make it so you dont have to do the calculations).
I would be inclined to create an empty gameobject on the fly, do the manipulation, get the coordinates, and then destroy it.
That might also be a factor if you are finding the rotated value just once or doing it continuously.

edited typo: I wrote "included" when I meant to write "inclined"

 

ha that worked so well! Thank god I don't have to learn about Quaternions! (although I really probably should at some point, I suppose). Thanks a lot for the help, guys. You just saved me a lot of sweat and tears.