quaternion question

[Keith W. <kw...@cs...>]

I have an object that has not been rotated at all yet, so its starting 
quaternion Q is (1,0,0,0).  I have a vector V (x,y,z) that specifies a 
3D pointing or facing direction.  I would like to take the object's 
facing direction, which starts out (0,0,1), straight down the z axis, 
and orient it such that it faces in the same direction as the vector V.  
I realize this doesn't entirely specify an orientation since there is 
still the question of how the object is "rolled" around the facing 
vector, but I am not concerned with that right now.  For this specific 
application it doesn't even matter because the object in question is 
perfectly cylindrical around the z axis so rolling doesn't mean 
anything.  I just want to make it point in the direction of the vector V.

How do I do this?  Any ideas?

Thanks, as always.


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Keith Wiley         kw...@cs...         http://www.unm.edu/~keithw

"Yet mark his perfect self-contentment, and hence learn his lesson,
that to be self-contented is to be vile and ignorant, and that to
aspire is better than to be blindly and impotently happy."
                                           --  Edwin A. Abbott, Flatland
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