[vtkusers] vnl quaternion question

[Aron Helser]

Auto invQ = q.inverse();
Auto unRotPt = invQ  * rotPt * invQ.conjugate();

that ought to work....

On Mon, Dec 4, 2017 at 11:56 PM, Richard Frank <rickfrank at me.com> wrote:

> Hi,
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> I can rotation a point as below, but how to simply get back the original
> point?
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> vnl_vector_fixed<float,3> pt = {0,1,0};
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> vnl_vector_fixed<float,3> axis = {0,0,1};
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> vnl_quaternion<float> q = vnl_quaternion<float>(axis,45 * M_PI / 180.0);
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> auto rotPt = q * pt * q.conjugate();
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> // how to invert?
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> Auto unRotPt = q.inverse() * rotPt; // doesn’t seem to work
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> Thanks
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> Rick
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