Re: quaternion question

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

Works beautifully.  Thanks.  I guess I should have been able to find that 
on my own.  Sorry, but thanks.

On Wed, 23 Feb 2005, James W. Walker wrote:

> On Feb 23, 2005, at 11:02 PM, Keith Wiley wrote:
>
>> 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?
>
> How about using Q3Quaternion_SetRotateVectorToVector?
> --
> <http://www.jwwalker.com/>
>
>
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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
________________________________________________________________________