[Papervision3D] Quaternion rotation

[Jim Armstrong]

Joe McKeown wrote:
> Pardon me if this has already been addressed but I have yet to find an
> answer specific to PV3D.
>
> I'm trying to allow user interaction with a mouse to rotate a 3D object.
> I'm limiting rotation to 2 axes: X & Y.  Euler rotations have the ugly
> reality of gimbal lock so I'm exploring the use of Quaternion math to
> handle the rotations.  There's plenty of info about the algorithms and
> even some Actionscript implementations (e.g., Sandy's QuaternionMath
> class) but I can't seem to get anything to work.  Generally, I can
> follow the concepts and math but without a specific example/solution for
> this problem I'm a bit lost.  My experimenting has proven frustrating
> and I'm not sure where I'm going wrong.
>
> Does anyone have some input and/or direction as to translating 2D mouse
> coordinates to 3D rotation of an object?
>   
If you're limiting rotation to two axes, by controlling the order, you 
should not lock.

For example, if rotating along X and Y,  apply Euler angles in the order 
X, Z, Y.  There was a good gamedev.net article on this topic, but the 
URL escapes me.

Quaternions may be overkill for what you want, but I think there was an 
example implementation in the Flash MX 2004 Magic book,

http://www.amazon.com/Macromedia-Flash-MX-2004-Magic/dp/0735713774

complete with code.

good luck!

- jim
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-- 
Jim Armstrong::Mathematician::Algorithmist::Programmer
Singularity::www.algorithmist.net