User talk:Randallbsmith

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Quaternion and spatial rotation

Hello. In your contribution from September 2009, you state:

Added "The radius of the sphere represents the size of the rotation." Best to state explicitly, esp. after previous sentence.)

I think that "represents" is misleading. It suggests that the length of the vector is equal, or at least proportional, to the angle of the rotation. That is not true. The relation is far mor complex, the length of the vector is equal to the cosine of half the angle of the rotation. So I replaced "respresents" with "is related to".

I think this solution keeps the idea of the relation between both quantities, while avoiding to mislead the reader. MathsPoetry (talk) 13:23, 1 January 2010 (UTC)[reply]